20 Hardest SAT Math Questions With Explanations

Updated:
July 2, 2024
12 min read
Expert Reviewed
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”Mary

Reviewed by:

Mary Banks

Former Admissions Committee Member, Columbia University

Reviewed: 5/15/24

Keep reading to learn how to solve the most challenging SAT math questions.

The SAT Math section presents various problems to test your problem-solving and reasoning skills. To help you ace this part of the exam, we've compiled a comprehensive guide that breaks down the math topics covered on the exam. 

We’ll also provide detailed explanations and strategies to tackle the 20 hardest SAT math questions

What Is the SAT Math Section?

The SAT Math section evaluates students' mathematical skills through multiple-choice and grid-in questions. It comprises two subsections: one where a calculator is permitted and another where it is not. 

With 58 questions to be completed in 80 minutes, this section of the SAT challenges students to apply mathematical reasoning and problem-solving strategies under time constraints. 

What Topics Are Covered in the Math Section of SAT?

The Math section covers several topics, including algebra, geometry, trigonometry, and probability. Students can specifically expect questions on linear equations, quadratic equations, functions, graphs, geometry concepts (angles, triangles, circles, and polygons), trigonometric functions, and identities. 

The SAT Math section may also include questions involving statistics and data interpretation, which requires students to analyze and interpret graphs, tables, and charts. 

20 Hardest SAT Math Questions

Here’s our list of the most difficult SAT math questions with solutions to help you prepare for this exam. 

Question 1

Simplify the expression: 3x2-5x+2x-2

Solution

To simplify this expression, we can use long division.

3x-2+2 divided by x-2

=3x+1

Therefore, the simplified expression is 3x+1.

Question 2

If f(x) = x2-4/x-2, what is the value of f(2)?

Solution

To find the value of f(2), we substitute x=2 into the function f(x)

f(2)= 22-4/2-2

4-4/0

Since division by zero is undefined, f(2) is undefined.

Question 3

In the xy-plane, the point (-2, 3) is reflected across the x-axis to produce point P. Point P is then translated 3 units to the left to produce point Q. What are the coordinates of point Q?

Solution

When a point is reflected across the x-axis, the y-coordinate changes sign. So, the y-coordinate of point P is -3.

To translate a point 3 units to the left, subtract 3 from the x-coordinate.

Thus, the coordinates of point Q are (-5, -3).

Question 4

If sin x= 3/5 , and x is in quadrant II, what is the value of cos x?

Solution

In quadrant II, both sine and cosine are positive.

Since x=3/5, and we know that sin2x+cos2x=1, we can use pythagoras identity to find cosx.

cos2x=1-sin2x

=1-(3/5)2

1-9/25

16/25

Since cosine is positive in quadrant II, cosx=√16/25=4/5

Question 5

A rectangle has an area of 24 square units. If its length is 3 units longer than its width, what is the perimeter of the rectangle?

Solution

Let the width of the rectangle be w units. Then, its length is w+ 3 units

The area of a rectangle is given by the formula A= length X width

So, we have the equation 24=(w+3 X  w) 

Expanding and rearranging, we get the quadratic equation w2+3w-24=0

Solving for w, we find w=4 (since width cannot be negative)

Therefore, the length of the rectangle is 4+3=7 units

The perimeter of the rectangle is 2 X (4+7)=22 units

Question 6

Triangle ABC is equilateral, and triangle DEF is equilateral. The ratio of the area of triangle ABC to the area of triangle DEF is 16:9. What is the ratio of the perimeter of triangle ABC to the perimeter of triangle DEF?

Solution

In an equilateral triangle, all sides are equal, and all angles are 60∘. 

The ratio of the areas of two similar figures is equal to the square of the ratio of their corresponding side lengths.

So, the ratio of the side lengths of triangle ABC to triangle DEF is √16/9= 4/3

Question 7

A circle with a radius of 5 is inscribed in a square. What is the area of the shaded region?

Solution

To find the area of the shaded region, we need to subtract the area of the circle from the area of the square.

The area of the square is equal to the side length squared, so 102=100 square units

The area of the circle is π2= π x 52=25π square units

Therefore, the area of the shaded region is 100-25π square units

Question 8

The ratio of the length of a rectangle to its width is 4:3. If the length is increased by 2 units and the width is decreased by 1 unit, the ratio becomes 2:1. What is the perimeter of the original rectangle?

Solution

Let the length of the original rectangle be 4x and the width be 3x

According to the given ratios, we have the equation 4x+2/3x-1=2/1

Solving for x, we find x=1

Therefore , the original length is 4 X 1= 4 units, and the original width is 3 X 1=3 units

The perimeter of the original rectangle is 2 X (4+3)=14 units

Question 9

In a right triangle, the length of the altitude drawn to the hypotenuse is equal to half the length of the hypotenuse. What is the measure of the acute angle formed by the altitude and the hypotenuse?

Solution

Let the length of the hypotenuse be 2x units, and the length of the altitude be x units. By the Pythagorean theorem, the lengths of the other two sides are x units each.

Therefore, the triangle is an isosceles right triangle, and the acute angle formed by the altitude and the hypotenuse is 45∘

Question 10

A rectangle has a perimeter of 30 units. If its length is twice its width, what are the dimensions of the rectangle?

Solution

Let's denote the width of the rectangle as w units. Since the length is twice the width, the length l can be expressed as 2w units

The perimeter of a rectangle is given by P = 2l +2w. Substituting the given values, we get:

30=2(2w)+2w

30=4w+2w

30=6w

Dividing both sides by 6

w=30/6

w=5

Now that we have the value of w, let’s find the length l, which is twice the length

l=2w=2(5)=10

So, the length of the rectangle is 10 units

Question 11

A sequence is defined recursively as follows: a1=3 and a πn+1=1/2an+1 for n>1. What is the value of a10?

Solution

To find the value of a10 in the sequence, let’s start by finding the values of a2, a3, and so on until a10 using this formula

a2=1/2a1+1

a3=1/2a2+1

a4=1/2a3+1

a10=1/2a9+1

Since we have a1=3, we can start with this value

a2= 1/2(3)+1=3/2+1=5/2

a3= 1/2(5/2)+1=5/4+1=9/4

Continuing this process, we eventually find

a10= 1/2(9/2)+1=9/4+1=134

So, the value of a10 in the sequence is 13/4

Question 12

If f(x)=2x-3/x+1, what is the value of f-1(1)?

Solution

To find f-1(1), we first need to find the value of x such that f(x) = 1

Given that f(x)=2x-3/x+1, we set f(x) = 1 and solve for x

 1=2x-3/x+1

To solve this equation, we cross-multiply

2x-3=x+1

Subtract x from both sides

x-3=1

Add 3 to both sides

x=4

Now that we have found the value of x, we can substitute it into the inverse function f-1(x) to find the corresponding value

f-1(1)= 4+1=5

Therefore f-1(1)=5

Question 13

In a right triangle, the length of the altitude drawn to the hypotenuse is 8 units, and one leg of the triangle is 15 units. What is the length of the other leg?

Solution

To solve this problem, we'll use the geometric property of right triangles involving altitudes drawn to the hypotenuse.

Given:

Length of the altitude drawn to the hypotenuse (height) = 8 units

Length of one leg of the triangle (base) = 15 units

Let's denote the length of the other leg (unknown side) as x

According to the geometric property, the product of the lengths of the segments of the hypotenuse split by an altitude is equal. Therefore, we can write the equation

8 X x= 15 X (x+8)

Now, let's solve for x

8x= 15x+120

8x-15x=120

-7x=120

x=-120/7

However, the length of a side cannot be negative, so we discard the negative solution.

Therefore, the length of the other leg of the right triangle is x=120/7units

Question 14

Given a triangle ABC where AB=8, BC =15, and AC=17, find the measure of angle A

Solution

To find the measure of angle A in triangle ABC, we can use the Law of Cosines

The Law of Cosines states that for any triangle with sides a, b, and c and angle C opposite side c, the following equations holds

c2=a2+b2-2abcosC

In this case, a=BC=15, b=AC=17, and c=AB=8

Let's plug these values into the Law of Cosines to find the cosine of angle A

82=152+172-2(15)(17) cos A

64=225+289-510 cos A

64=514-510 cos A

510 cos A=514-64

510 cos A=450

cos A = 450510

cos A= 4551

Now, we can use the inverse cosine function to find the measure of angle A

A= cos-1(45/51)

A cos-1 (0.882)

A29.47

Therefore, the measure of angle A in triangle ABC is approximately 29.47

Question 15

If cos x=4/5 and x is in quadrant IV, what is the value of sin x?

Solution

Since x is in quadrant IV, cosine is positive, but sine is negative. Given that cos x=45, we need to find the value of sin x

sin2x=1-cos2x

sin2x=1-452

sin2x=1-2025

sin2x= -2024

Since sine is negative in quadrant IV, we take the negative square root

sin x= -√-2024

sin x = -√-1 X 2024

sin x = -√2024i

Therefore, the value of sin x is -√2024i in quadrant IV

Question 16

The sum of the first n terms of an arithmetic sequence is 2n2+n. What is the nth term of the sequence?

Solution

To find the nth term of an arithmetic sequence, we need to use the formula for the sum of the first nth term of an arithmetic sequence.

The formula for the sum of the first n terms of an arithmetic sequence is given by

Sn=n/2(a1+an)

Where Sn is the sum of the first n terms, a1 is the first terms, an is the nth term, and n is the number of terms

In this problem, the sum of the first n terms is given as 2n2+n. so, we have

2n2+n=n/2(a1+an)

We can rewrite this equation as:

4n2+2n= n(a1+an)

4n+2=a1+an

Since the sequence is arithmetic, the difference between consecutive terms is constant. So, an-a1=(n-1)d, where d is the common difference

Now, we can find the value of d by subtracting the first term from the second term

d=a2-a1= (a1+ (n-1)d)-a1

d=a1+ (n-1)d-a1

d=nd

1-n

So, d=1

Now that we have the common difference, we can find the nth term by substituting d=1 into the equation an=a1+ (n-1)d

an= a1+ (n-1)d

an=a1+ (n-1)(1)

an= a1+ n-1

Now, we need to find a1 in terms of n. We know that a1 is the first term, so it is the term when n=1. Substituting n=1 into the sum formula

2(1)2+1=2+1+3

Thus, a1=3

Finally, substituting a1=3 into the formula for the nth term:

an=3+n-1

an= 2+n

Therefore, the nth term of the sequence is 2+n

Question 17

A square and an equilateral triangle have equal perimeters. If the side length of the square is 12, what is the side length of the equilateral triangle?

Solution

Let's denote the side length of the equilateral triangle as s

The perimeter of the square is equal to the sum of the lengths of its four sides, so it's 4 X 12=48

The perimeter of an equilateral triangle is equal to the sum of the lengths of its three sides, so it's 3s

Since the perimeters of the square and the equilateral triangle are equal, we have the equation:

48=3s

Now, let's solve for s

s=48/3

s=16

Therefore, the side length of the equilateral triangle is 16

Question 18

In a circle with a radius of 6, what is the length of an arc that subtends a central angle of 120o?

Solution

To find the length of an arc that subtends a central angle of 120o in a circle with a radius of 6, we use the formula:

 Arc length = n/360 X 2πr

Where,

n is the measure of the central angle in degrees.

r is the radius of the circle.

In this case, n = 120o and r=6

Let's plug these values into the formula:

Arc length =120/360 X 2π X 6

Arc length = 1/3 X 2 X 22/7 X  6

Arc length = 1/3 X 44/7 X 6

Arc length =1/3 X 26/47

Arc length=88/7

So, the length of the arc that subtends a central angle of 120 in a circle with radius 6 (using π = 22/7) is 88/7units

Question 19

If f(x)= x2-4x+5, what is the value of f(2)?

Solution

To find the value of f(2) for the function f(x) = x2-4x+5, we substitute x=2 into the function

f(2)=(2)2-4(2)+5

f(2)=4-8+5

f(2)=1

Therefore, the value of f(2) is 1

Question 20

A car travels from Town A to Town B at an average speed of 60 mph and returns to Town A at an average speed of 40 mph. What is the average speed for the round trip?

Solution

To find the average speed for the round trip, we can use the formula for average speed

Average speed= Total distance/Total time

Let's denote:

d as the one-way distance between Town A and Town B.

t1 as the time taken to travel from Town A to Town B.

t2 as the time taken to return from Town B to Town A

Since the distance traveled is the same for both legs of the trip, d is the same for both.

For the first leg of the trip:

t1= d/Speed= d/60

For the second leg of the trip:

t2= d/Speed= d/40

The total time for the round trip is t1+t2

Total Time= d/60+d/40=2d+3d/120=5d/120=d/24

Now, let's find the total distance traveled:

Total distance = d+d=2d

Now, we can use the formula for average speed to find the average speed for the round trip:

Average speed= Total Distance/Total Time= 2d/d24=2 X 2= 48 mph

Therefore, the average speed for the round trip is 48 mph

No Calculator Allowed SAT Math Questions

Take a look at these Math questions that don’t require a calculator to solve.

Question 1

In a bag, there are 8 red balls, 5 blue balls, and 3 green balls. If a ball is randomly chosen from the bag, what is the probability that it is either red or blue?

Solution

To find the probability of choosing either a red or blue ball, we first need to determine the total number of balls in the bag, and then find the number of red and blue balls.

Total number of balls = 8 (red) + 5 (blue) + 3 (green) = 16

Number of red and blue balls = 8 (red) + 5 (blue) = 13

The probability of choosing either a red or blue ball is given by the ratio of the number of red and blue balls to the total number of balls:

Probability = Number of red and blue balls / Total number of balls

Probability = 13/16

Therefore, the probability of choosing either a red or blue ball is 13/16

Question 2

A rectangle has a length that is three times its width. If the perimeter of the rectangle is 48 inches, what is the length of the rectangle?

Solution

Let's denote:

L as the length of the rectangle.

W as the width of the rectangle.

We're given that the length of the rectangle is three times its width, so we can write the equation:

L=3W

The perimeter of a rectangle is given by the formula:

P=2(L+W)

We're also given that the perimeter of the rectangle is 48 inches, so we can write the equation:

48=2(L+W)

Now, we'll substitute L=3W into the perimeter equation:

48 =2(3W+W)

48=2(4W)

48=8W

Now, we'll solve for W

W=48/6

W=6

Now that we've found the width of the rectangle, we can find the length using the equation L=3W

L=3(6)

L=18

Therefore, the length of the rectangle is 18 inches

SAT Math Questions Where Calculators Are Allowed 

Unlike the ones where calculators are not required, these questions require critical thinking, knowing formulas, and calculations. Here are some SAT math examples in this category:

Question 1

The sum of the measures of the interior angles of a polygon is 1980 degrees. How many sides does the polygon have?

Solution

To find the number of sides of the polygon, we can use the formula for the sum of the measures of the interior angles of a polygon: 

Sum of interior angles = (n-2) X 180o

Where n is the number of sides of the polygon.

We're given that the sum of the measures of the interior angles of the polygon is 1980o, so we can write the equation:

1980= (n-2) X 180

Now, let’s solve for n

1980 = 180n - 360

1980 +360 = 180n

2340= 180n

n= 2340/180

n=13

Therefore, the polygon has 13 sides

Question 2

A circle has a radius of 5 inches. What is the area of the sector formed by a central angle of 60?

Solution

To find the area of the sector formed by a central angle of 60 in  a circle with a radius of 5 inches, we can use the formula for the area of a sector:

Area of sector = Central angle/360∘ X πr2

Substituting π=22/7, Central angle = 60, and r = 5, we have

Area of sector 60/360 X (22/7) X (5)2

Area of sector= 1/6 X (22/7)(5)2

Area of sector=1/6 X 22/7 X 25

Area of sector=22 X 25/7 X 6

Area of sector=550/42

Area of sector = 13.10

Therefore, the area of the sector formed by a central angle of 60 in a circle with a radius of 5 inches is 13.10 square inches

Tips on How to Tackle Difficult Math Questions

Solving maths questions can be challenging, but by understanding the question, identifying key concepts, and knowing how to work backward, you can approach with confidence. Here are strategies to help you tackle difficult math questions

  • Understand the Question: Read the question carefully, identifying key information and what is being asked. Break down complex problems into smaller, more manageable parts.
  • Identify Key Concepts: Recognize the mathematical concepts or formulas needed to solve the problem. Review relevant formulas and concepts before attempting to solve the question.
  • Work Backwards: Sometimes, starting from the answer choices and working backward can help you eliminate incorrect options or narrow down possibilities.
  • Draw Diagrams or Visual Aids: Visualizing the problem by drawing diagrams or sketches can provide clarity and help you better understand the problem.
  • Use Process of Elimination: If you're unsure about an answer, eliminate choices that are clearly incorrect. This can increase your chances of selecting the correct answer, even if you're not entirely sure.
  • Practice, Practice, Practice: Practice solving several difficult questions to improve your problem-solving skills and build confidence. Review your mistakes and learn from them. Try our mock SAT exams to help you improve your skills immensely!
  • Stay Calm and Focused: Difficult math questions can be intimidating, but maintaining a calm and focused mind can help you approach the problem with clarity.
  • Manage Your Time: SAT Math sections are timed, so practice managing your time effectively. If you're struggling with a difficult question, don't spend too much time on it. Move on to easier questions and come back to it if you have time remaining.
  • Check Your Work: After solving a difficult question, double-check your calculations and ensure that your answer makes sense in the problem's context. Also, remember to review your work for any careless errors.

If you follow these strategies, you'll be better equipped to tackle the most difficult SAT Math questions with ease. Remember to practice these techniques regularly, and don't be afraid to seek help when needed. 

FAQs: 20 Hardest SAT Math Questions With Explanations

Here are answers to frequently asked questions on the hardest SAT math questions.

1. Should You Focus on the Hardest Math Question on the Test?

While challenging questions may give higher point values, don't spend too much time on them at the expense of easier questions. Focus on answering as many questions as you can accurately within the allotted time.

2. How Many Math Questions are on the SAT?

The SAT Math section consists of a total of 58 questions. These questions are divided into two subsections: one where a calculator is allowed and one where a calculator is not allowed. 

3. What Are the Most Common Questions on the SAT?

While specific question types may vary, common question formats include algebraic expressions, linear equations, geometric figures, functions, and data interpretation.

4. How Many Questions are on the SAT Math Section Where a Calculator is Allowed?

In the SAT Math section where a calculator is allowed, there are a total of 38 questions. This subsection comprises 30 multiple-choice questions and 8 grid-in questions. 

5. How Can I Prepare for SAT Math Questions Where a Calculator is Not Allowed?

To prepare for SAT Math questions where a calculator is not allowed, focus on strengthening mental math skills, mastering basic arithmetic operations, and understanding key mathematical concepts. Additionally, review the College Board's guidelines on what functions and formulas are provided in the test booklet for reference.

6. Is There a Penalty for Incorrect Answers on the SAT Math Section?

No, there is no penalty for incorrect answers on the SAT Math section. Your score is determined solely based on the number of questions you answer correctly.

Final Thoughts

Mastering SAT Math requires both knowledge and strategy. By understanding the test format, honing problem-solving techniques, and familiarizing yourself with key mathematical concepts, you can approach difficult math questions with confidence. 

Remember to manage your time effectively during the exam and stay calm under pressure. With dedication and preparation, you'll be well-equipped to tackle any math challenge and achieve your desired score on the SAT. 

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