ACT Math : Algebra

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #23 : How To Find The Solution To An Equation

Sally sells hair accessories. Her monthly fixed costs are $150. It costs her $5 to make each barrette, and she sells them for $10 each.

If Sally wants to make a profit of $250, how many barrettes must she sell?

Possible Answers:

Correct answer:

Explanation:

Let  be equal to the number of barrettes sold.

Revenue will be equal to .

Costs will be equal to .

The equation to solve becomes .

To reach the profit goal of $250, we need to calculate the value of .

Example Question #301 : Algebra

What are the values for x that satisfy the equation (x-d)(x+c)=0?

 

Possible Answers:

dc

-dc

d and c

d and -c

–d and c

Correct answer:

d and -c

Explanation:

Set each component of this equation equal to zero and solve for d and c.

(x-d)(x+c)=0

x-d=0

d=0

x+c=0

x=-c

 

 

Example Question #302 : Algebra

If A + B = C and B – C = 3, what does A equal?

Possible Answers:

6

9

3

3

9

Correct answer:

3

Explanation:

This question can be solved using substitution. There are several ways to subsitute, but one possible method is to substitue (A+B) for C in  the equation B-C=3: B-(A+B)=3. This simplifies to (B-A-B=3) (don't forget to distribute the negative!). Since (B-B)=0, -A must equal 3 (-A=3). If we divide both sides by -1, A=-3. If you got an answer of positive 3, you may have forgotten to divide both sides by -1.

Example Question #303 : Algebra

The population of a bird species is modeled by the following equation: 

,

 

where represents the number of years from the present. How many years will it take the population to reach 130 birds (rounded to the nearest tenth)?

Possible Answers:

280.8

20.4

12.2

23.0

38.5

Correct answer:

20.4

Explanation:

Plugging in 130 for P, the equation becomes 130 = (11/8)x + 102.  Solving for x, we obtain x = 20.4 years.

Example Question #304 : Algebra

What is the value of c when 3c + 4 = 2c  7?

Possible Answers:

1

0

No Solution

11

11

Correct answer:

11

Explanation:

First put the variables on one side by subtracting 2c on both sides to get c + 4 = –7. Then subtract the 4 on both sides to arrive at your answer, c = 11. 

Example Question #305 : Algebra

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

Possible Answers:

61.8

65.0

62.3

51.2

Correct answer:

61.8

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.

Example Question #29 : How To Find The Solution To An Equation

Which of the lines below is not parallel to 4x – 3y = 17 ?

Possible Answers:

–y= –(4/3)x – (17/3)

8x  6y = 34

2x  1.5y = 8.5

8x + 6y = 34

Correct answer:

8x + 6y = 34

Explanation:

For a line to be parallel with another, the slopes must be equal. All of the equations have a slope of 4/3 except 8x +6y=34.

Example Question #30 : How To Find The Solution To An Equation

If the expression x4 + 3cx  2 is equal to 5 when x = 1, what is the value of c? 

Possible Answers:

3

2

2

1

Correct answer:

2

Explanation:

Plugging in 1 into the equation for x and solving for c yields 2.

Example Question #306 : Algebra

What is the slope of the line 7y – 4x = 27

Possible Answers:

Correct answer:

Explanation:

Adding 4x to both sides of the equation and dividing by 7 yields a slope of 4/7.

Example Question #32 : How To Find The Solution To An Equation

If you drove at an average speed of 78 miles per hour, what distance, in miles, did you drive in 140 minutes? 

Possible Answers:

182

4,680

156

1.8

Correct answer:

182

Explanation:

140 minutes is 7/3 of an hour. Multiplied by the speed of 78mph, we obtain 182 miles traveled.

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