Math Mod Unit 9 Lesson 10

For a given interest rate, simple interest varies jointly as principal and time. If $2,500 left in an account for 5 years earns interest of $360, how much interest would be earned if you deposit $5,600 for 9 years?

$1,451.52

If y varies jointly as x and z , and y=30 when x=10 and z=8 , find y when x=15 and z=20.

112 1/2

The work W done when lifting an object varies jointly with the mass m of the object and the height h that the object is lifted. The work done when a 150 kg object is lifted 3 meters is 450 joules. How much work is done when lifting a 100 kg object 1.5 meters?

150 joules

The volume of a pyramid varies jointly as its height and the area of its base. A pyramid with a height of 10 feet and a base with area of 30 square feet has a volume of 100 cubic feet. Find the volume of a pyramid with a height of 17 feet and a base with an area of 27 square feet.

153 cubic feet

Wind resistance varies jointly as an object's surface area and velocity. If an object traveling at 60 miles per hour with a surface area of 15 square feet experiences a wind resistance of 200 Newtons, how fast must a car with 45 square feet of surface area travel in order to experience a wind resistance of 250 Newtons?

25 miles per hour

The volume of gas varies directly as the temperature and inversely as the pressure. If the volume is 50 cubic inches when the temperatures is 300 K and the pressure is 20 pounds per square inch, what is the volume when the temperature is 270 K and the pressure is 30 pounds per square inch?

30 cubic inches

If y varies jointly as x and z , and y=8 when x=12 and z=4 , find z when y=5 and x=7.

4 2/7

If y varies directly as x and inversely as z , and y=25 when x=5 and z=3, find y when x=10 and

6

joint variation

a relationship where one variable varies directly as the product of two other variables