ACT Math : Expressions

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #1 : Evaluating Expressions

Evaluate 4x+ 6x – 17, when x = 3. 

Possible Answers:

37

30

13

17

36

Correct answer:

37

Explanation:

Plug in 3 for x, giving you 36 + 18 – 17, which equals 37.

Example Question #1 : How To Evaluate Algebraic Expressions

John has a motorcycle. He drives it to the store, which is 30 miles away. It takes him 30 minutes to drive there and 60 minutes to drive back, due to traffic. What was his average speed roundtrip in miles per hour?

Possible Answers:

30 mph

60 mph

50 mph

40 mph

45 mph

Correct answer:

40 mph

Explanation:

The whole trip is 60 miles, and it takes 90 minutes, which is 1.5 hours.

Miles per hour is 60/1.5 = 40 mph

Example Question #941 : Algebra

If (xy/2) – 3= –9, what is the value of w in terms of x and y?

Possible Answers:

3xy + 6

(1/3)xy + 6

(1/2)xy – 3

w = 3 + (xy/6)

3xy – 6

Correct answer:

w = 3 + (xy/6)

Explanation:

–3w = –9 – (xy/2)

w = 3 + (xy/6)

Example Question #2439 : Act Math

Evaluate 5x+ 16x + 7 when x = 7

Possible Answers:

364

362

363

365

361

Correct answer:

364

Explanation:

Plug in 7 for x and you get 5(49) + 16(7) + 7 = 364

Example Question #2440 : Act Math

Let \dpi{100} \small a\&hash;b=(2a-b)^{2} for all integers \dpi{100} \small a and \dpi{100} \small b. Which of the following is the value of \dpi{100} \small -2\&hash;5?

Possible Answers:

\dpi{100} \small 1

\dpi{100} \small 81

\dpi{100} \small -9

\dpi{100} \small 144

\dpi{100} \small -81

Correct answer:

\dpi{100} \small 81

Explanation:

In order to solve the expression, replace \dpi{100} \small a with \dpi{100} \small -2 and \dpi{100} \small b with \dpi{100} \small 5 in the definition given:

\dpi{100} \small a\&hash;b=(2(-2) -5)^{2}

\dpi{100} \small a\&hash;b=(-4 -5)^{2}

\dpi{100} \small a\&hash;b=(-9)^{2}

\dpi{100} \small a\&hash;b=81

Example Question #11 : Evaluating Expressions

What is the value of x that satisfies the equation 5(x+2)=12x-5 ?

Possible Answers:

-\frac{15}{17}

1

0

\frac{15}{7}

\frac{15}{11}

Correct answer:

\frac{15}{7}

Explanation:

Distributing the 5 on the left side of the equation gives you 5x+10=12x-5.

Subtracting 5x from both sides of the equation gives you 10=7x-5.

Adding 5 to both sides of the equation gives you 15=7x.

Dividing each side of the equation by 7 gives you \frac{15}{7}=x.

Example Question #11 : Evaluating Expressions

If \small a = 2 and \small b = 4 , what is \small -4(ab)^{3} + (3a - 2b)?

Possible Answers:

-2050

-2046

-32,770

2046

2050

Correct answer:

-2050

Explanation:

\small -4(2\times 4)^{3} + \left ( 3\times 2 - 2\times 4 \right )

\small -4(512) + (6-8)

\small -2048 -2

\small -2050

Example Question #12 : Evaluating Expressions

8 less than 4 times a number is 76. Find the number.

Possible Answers:

Correct answer:

Explanation:

Example Question #11 : Evaluating Expressions

Let and .  Solve zx^{y}

Possible Answers:

Correct answer:

Explanation:

Substitute the given values into the variables to get:

4(2^{3})= 4(8)= 32

Example Question #15 : Evaluating Expressions

Bob needs to order  candy bars from a warehouse. The website he is ordering from shows that the candy bars come in cases of  boxes with candy bars in each box. It is not possible to order partial cases. What is the fewest amount of cases that Bob should order?

Possible Answers:

Correct answer:

Explanation:

The answer is .

Bob must order full cases, which contain  boxes of candy bars with  bars per box. This comes out to a total of  candy bars per case. An order of  cases comes out to  candy bars which is not enough. However if he orders one more case, the total comes out to  candy bars which allows him to barely surpass his needed amount of  bars.

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