ACT Math : Expressions

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #11 : How To Evaluate Algebraic Expressions

Solve for :

Possible Answers:

Correct answer:

Explanation:

The answer is .

To solve this equation for , first distribute the  to make the equation

. Next, subtract from both sides to leave you with . Finally, divide both sides by  to determine that .

Example Question #17 : Evaluating Expressions

If three chairs cost , what is the cost of chairs?

Possible Answers:

Correct answer:

Explanation:

The answer is .

If three chairs cost , each chair costs . To determine the cost of two chairs, multiply .

Example Question #11 : How To Evaluate Algebraic Expressions

Evaluate the expression  for 

Possible Answers:

Correct answer:

Explanation:

The answer is 

To solve this expression subsitute  for . This results in . Simplify to get  as the answer.

Example Question #19 : Evaluating Expressions

If 40% of  equals 8, then 

Possible Answers:

Correct answer:

Explanation:

The equation can be set up as follows:

Solve for 

Now that we know the value of , we can plug it in to our final equation:

Remember, in this scenario, we must follow proper order of operations, where power is taken in consideration before multiplication.

In other words, 20 is squared first, giving 400. 

In our last step, we multiple 400 by 0.5, giving our final answer: 200

*Note, the other answer choices generally consist of answers at other steps of the problem or answers arrived at when not following proper order of operations. Be careful when answering questions like these, as they often have other answer choices meant to catch your mistake on the ACT.

Example Question #20 : Evaluating Expressions

If , then what is

?

Possible Answers:

Correct answer:

Explanation:

One can arrive to the answer two ways. They can either use FOIL then plug in  for or they can plug in  for  first, and then solve.

We recommend using the latter approach, as it saves more time, an important skill to recognize to be successful on the ACT.

By plugging in  for , we have:

Which simplifies to,

 or 

 

Example Question #21 : How To Evaluate Algebraic Expressions

What is the value of z that satisfies the equation: 10(z – 6) = 8z + 4

 

Possible Answers:

32

28

34

5

32

Correct answer:

32

Explanation:

Distribute: 10z – 60 = 8z + 4

Move all like terms together: 2z = 64

Solve: z = 32

 

 

Example Question #22 : Evaluating Expressions

If , then which of the following is an expression for in terms of  and ?

Possible Answers:

Correct answer:

Explanation:

Divide both sides by , giving you

.

Example Question #23 : Evaluating Expressions

Find the value of   where:

 

Possible Answers:

Correct answer:

Explanation:

This problem requires utilization of the opposite operations to both sides principle.

 

 

Adding +2 to both sides yields

 

 

Subtracting 2y from both sides yields

 

 

Example Question #51 : Expressions

Sally is ordering snacks for her class trip. She needs 85 cookies. The cookies come in cases of 6 boxes, with 7 cookies in each box. Sally can't order a partial box. What is the smallest number of cases she should order? 

Possible Answers:

1

4

6

2

3

Correct answer:

3

Explanation:

We first determine how many cookies are in each box. There are 7 cookies in a box, multiplied by 6 boxes, making 42 cookies in a case. We then divide the total number of cookies she needs, 85, by the number in each case, 42, giving us 2 with a remainder. This means Sally must order 3 cases of cookies.

Example Question #52 : Expressions

A company rents cars for a rental fee of $37.00 per day, with an additional charge of $0.45 per mile driven. Which of the following expressions represents the cost, in dollars, of renting the car for 2 days and driving it m miles?

Possible Answers:

37m + 45

37m + 0.45

74m + 45

0.45m + 37

0.45m + 74

Correct answer:

0.45m + 74

Explanation:

To determine cost we add the initial rental fee of $37, times two days giving us $74 plus the mileage rate, 0.45,  times the number of miles. Giving an equation of 0.45m+74.

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