Equations / Inequalities
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ACT Math › Equations / Inequalities
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.
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.
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
.
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.
Translate into an algebraic expression:
One third of the difference of a number and 3 equals five times the number.
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
Three consecutive even numbers add to 42. What is the middle number?
Explanation
Let = 1st even number,
= 2nd even number, and
= 3rd even number.
Then the equation to solve becomes .
Thus , so the middle number is 14.
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
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.
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?
Explanation
Let = the number of birdhouses sold each month.
Substituting in 50 for gives an answer of 500, so the profit on 50 birdhouses is $500.
Three consecutive even numbers add to 42. What is the middle number?
Explanation
Let = 1st even number,
= 2nd even number, and
= 3rd even number.
Then the equation to solve becomes .
Thus , so the middle number is 14.