Writing and interpreting functions

Suppose y varies directly as x. If y = 30 when x = 8, find y when x = 4.

• 1.07

• 15

• 26

• 60

For a group of objects made of the same material, the weight of an object varies directly with its volume. If an object has a volume of 10 cubic inches and weighs 14 ounces, what is the constant of variation?

• 7/5

• 5/7

• 140

• 14

Translate into a variation equation.

m varies directly as the square of n

If y varies inversely with x, and y = 10 when x = 5, what is the value of y when x = 2?

• 15

• 5

• 25

• 20

Find the missing value of an inverse variation given,  (6, 6) and (x, 4)

y varies inversely with x. When y = 24, x = 3.

What is the value of y when x = 2?

• 36

• 8

• 16

• 12

The time it takes Mr. Smith to build a desk with his students in woodshop varies inversely with the number of students he has in class. Last semester it took 200 working hours for 8 students to build a desk. Write the equation to represent the situation.

• t = 1600/s

• t= .04s

• s = 1600/t

• s = .04t

If y varies inversely with x, and y = 6 when x = 3, what is the value of y when x = 9?

• 2

• 18

• 3

• 27

If y varies directly with x, and y = 15 when x = 3, what is the value of y when x = 6?

• 10

• 30

• 20

• 45

If y varies directly with x, and y = 14 when x = 7, find y when x = 5.

• 14

• None of These

• 8

• 10