IAAT Ratios and Proportional Reasoning 3

Question 1

If the ratio of x to y is 5:3 and y = 12, what is the value of x?

Accepted Answer

20

Answer

If 3 parts = 12, one part = 4, so x = 5 × 4 = 20.

Question 2

A runner completes 4 laps in 10 minutes. How many laps can the runner complete in 25 minutes at the same rate?

Accepted Answer

10 laps

Answer

Rate = 4 ÷ 10 = 0.4 laps per minute; 0.4 × 25 = 10 laps.

Question 3

A batch of paint requires blue and yellow in a 3:1 ratio. To make 40 gallons of this paint, how many gallons of yellow are needed?

Accepted Answer

10 gallons

Answer

Total parts = 3 + 1 = 4; yellow = (1/4) × 40 = 10 gallons.

Question 4

Which proportion correctly models this problem: '3 is to 7 as n is to 35'?

Accepted Answer

3/7 = n/35

Answer

The proportion 3/7 = n/35 keeps the same ratio structure with n corresponding to 3.

Question 5

If y is directly proportional to x, and y = 18 when x = 3, what is y when x = 7?

Accepted Answer

42

Answer

Constant k = y/x = 18/3 = 6; when x = 7, y = 6 × 7 = 42.

IAAT - Iowa Algebra Aptitude Test Practice Test