Integers

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ACT Math › Integers

Questions 1 - 10
1

Solve:

Explanation

This problem can be solved using common factors.

Rewrite using factors.

2

The number 9 is the second smallest integer with 3 factors, 1, 3, and 9. What is the sum of the factors of the smallest integer with only 3 factors?

4

7

13

15

17

Explanation

Here we must do two things. First we must find the smallest integer with 3 factors, then we must add those factors so that we can obtain our answer.

Looking at numbers less than 9 with only 3 factors, the only possibility is the number 4, whose factors are 1, 2, and 4.

The sum of these factors is 1 + 2 + 4 = 7

3

Solve:

Explanation

This problem can be solved using common factors.

Rewrite using factors.

4

What is the probability of selecting a prime number out of the following set?

{2, 6, 9, 17, 21, 47, 63, 71, 81}

3/9

4/9

5/9

6/9

9/4

Explanation

Probability is determined by dividing favorable outcomes, by possible outcomes. As there are 9 numbers in the given set, the number of possible outcomes is 9. In the given set, only 2, 17, 47 and 71 are prime numbers (divisible only by 1 and itself). Thus, there are 4 favorable outcomes, yielding a probability of 4/9.

5

A sliced cake can be equally split among 4, 5, or 6 people, with each person receiving the same number of slices. Which of the following answers represents a possible number of slices that the cake could have?

24

30

56

116

120

Explanation

If you divide the answer choices by 4, 5, and 6, 120 is the only choice that divides evenly by all three numbers.

6

If , , and , what does equal?

Explanation

To answer this question, we must substitute our given values into an equation and solve, remembering our order of operations.

First, we must take our values for each variable and substitute them into the equation given. Therefore, since we are told that , , and ,

Now that we have our values plugged in, we need to remember the order of operations in order to solve this problem. The order of operations goes as follows: parentheses, exponents, multiplication and division, and finally addition and subtraction. The first order of operations is to carry out any operations that are within parenthesis. Therefore, for this data:

We can now simply multiply these numbers together.

Our answer is .

7

A car averages 29 miles per gallon. If gas costs $3.75 per gallon how much money would need to be spent on gas to travel 1464.5 miles?

$189.38

$5491.88

$108.75

$50.5

None of the other answers

Explanation

The question is asking for the amount of money that would need to be spent on gas. Using the value given for the miles per gallon of the car and the amount of miles traveled it is possible to determine the gallons of fuel that will be required. This will be set up as 1464.5 miles travelled divided by the 29 miles per gallon that the car gets. This leaves us with 50.5 gallons of fuel used. From this point we can multiply the amount of fuel used, 50.5 gallons, by the price of fuel per gallon, $3.75, to obtain the amount of money that will spent on fuel, $189.38.

8

Restaurant

The menu above is from Lena’s Italian Kitchen. If you are going there for dinner, how many different combinations of a meal and a salad are there?

20

5

10

15

25

Explanation

Combinations = # first option * # second option

= # meals * # salads

= 5 * 4 = 20

9

In the sequence 3,         ,         , 24, what numbers can fill the two blanks so that consecutive terms differ by a common ratio?

6, 12

9, 18

10, 15

10, 17

12, 16

Explanation

If the common ratio is r, then the sequence can be rewritten as 3, 3r, , . We see then that , which gives us that r=2. Therefore, the missing terms are 6 and 12.

10

A sliced cake can be equally split among 4, 5, or 6 people, with each person receiving the same number of slices. Which of the following answers represents a possible number of slices that the cake could have?

24

30

56

116

120

Explanation

If you divide the answer choices by 4, 5, and 6, 120 is the only choice that divides evenly by all three numbers.

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