Equations / Inequalities

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ACT Math › Equations / Inequalities

Questions 1 - 10
1

Give the lines y = 0.5x+3 and y=3x-2. What is the y value of the point of intersection?

2

3

4

6

7

Explanation

In order to solve for the x value you set both equations equal to each other (0.5x+3=3x-2). This gives you the x value for the point of intersection at x=2. Plugging x=2 into either equation gives you y=4.

2

If y=0.35(300 2y), what is the value of y to the nearest tenth?

61.8

51.2

65.0

62.3

Explanation

Distributing the 0.35 to both the 300 and **–**2y leaves y=105 0.7y

Adding 0.7y to both sides and dividing by 1.7 gives 61.8.

3

A car averages miles per gallon. If gas costs per gallon, which of the following is closest to how much the gas would cost for this car to travel typical miles?

Explanation

To solve this problem you should divide the total number of miles by the miles per gallon , and then multiply by the cost of gas per gallon . This gives you , which is closest to .

4

The Teddy Bear Parade makes teddy bears. Their monthly fixed costs are $550. It costs $25 to make each bear and they sell for $50 each.

To make a profit of $750, how many teddy bears must be sold?

Explanation

Let = number of teddy bears sold.

Revenue:

Costs:

Profits = or

So the equation to solve becomes

So to make a profit of $750, 52 teddy bears must be sold.

5

Translate into an algebraic expression:

One third of the difference of a number and 3 equals five times the number.

\frac{1}{3}\left ( x-3 \right )=5x

\frac{1}{3}x-3=5

\frac{1}{3}x-3=5x

\frac{1}{3}\left ( x+3 \right )= 5x

3\left ( x-3 \right )=5x

Explanation

You have to form the difference first and must be enclosed in parentheses which gets multiplied by 1/3. The word "equals" means the "=" symbol

6

Three consecutive even numbers add to 42. What is the middle number?

14

10

12

16

18

Explanation

Let x = 1st even number, x+2 = 2nd even number, and x+4 = 3rd even number.

Then the equation to solve becomes x+(x+2)+(x+4)=42.

3x+6=42

Thus x=12,x+2=14,\ and\ x+4=16, so the middle number is 14.

7

If 5 + x is 5 more than 5,what is the value of 2_x_?

10

5

15

20

Explanation

5 more than 5 = 10

5 + x = 10

Subtract 5 from each side of the equation: x = 5 → 2_x_ = 10

8

Three consecutive positive numbers have the sum of 15. What is the product of these numbers?

20

45

75

120

30

Explanation

Define the variables as x = the first number, x + 1, the second number, and x + 2 the thrid number.

The sum becomes x + x + 1 + x + 2 = 15 so 3x + 3 = 15. Subtract 3 from both sides of the equation to get 3x = 12 → 3x/3 = 12/3 → x = 4

The three numbers are 4, 5, and 6 and their product is 120.

9

Pets Plus makes bird houses. Their monthly fixed expenses are $750. The cost for each bird house is $15. The bird houses sell for $40.

If Pets Plus sells 50 bird houses, what is the profit?

\$500

\$250

\$750

\$300

\$625

Explanation

Let x = the number of birdhouses sold each month.

Revenue=40x

Costs=15x+750

Profit = Revenue-Costs

=40x-15x-750

=25x-750

Substituting in 50 for x gives an answer of 500, so the profit on 50 birdhouses is $500.

10

Three consecutive even numbers add to 42. What is the middle number?

14

10

12

16

18

Explanation

Let x = 1st even number, x+2 = 2nd even number, and x+4 = 3rd even number.

Then the equation to solve becomes x+(x+2)+(x+4)=42.

3x+6=42

Thus x=12,x+2=14,\ and\ x+4=16, so the middle number is 14.

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