Functions (general)

If y varies directly as the cube of x, and y = 1000 when x = 5, find the value of y when x = 9.

The number of gallons g of fuel used on a trip varies directly with the number of miles m traveled. If a trip of 270 miles required 12 gallons of fuel, how many gallons are required for a trip of 400 miles?

• g=18

• g=22

• g=12

• g=30

In the table, y varies inversely with x.

What is the missing value?

y varies directly as x. If y = 15 when x = 12 find y when x = 32.

• 40

• -40

• 5

• -5

The sales at a baseball game vary directly with the number of people attending.  If sales for a game are $12,000 when 800 people attend, determine attendance if sales are $30,000

• 1200 people
• 1500 people
• 2000 people
• 2400 people

Solve for the unknown variable:

If a varies directly as b and a = 12 when b = 20, what is the value of b if a = 123? (no space)

If x = 2/3 and y = 24, then what is K?

Given that y varies inversely with x and y = 3 when x = 2, find y when x = 3.

• $y=\frac{1}{6}$

• $y=\frac{1}{2}$

• $y=6$

• $y=2$

P varies directly to the cube root of X and inversely as Y. Given that the constant is k, find the relation between P, X and Y.

• $P=\frac{kX^3}{Y}$

• $P=\frac{kX^{\frac{1}{3}}}{Y}$

• $P=kX^{\frac{1}{3}}Y$

• $P=\frac{kY^3}{X}$

If y varies inversely with x, and y = 15 when x = 5, what is the value of x when y = 9?

• 10

• 8.33

• 12

• 7.5