inverse variation

If z varies directly as x, and z = 30 when x = 8, find z when x = 4.

15

The distance needed to stop a car varies directly as the square of its speed. It requires 120 m to stop a car at 70 km/h. What distance is required to stop a car at 80 km/h?

156.73

If y varies inversely as x, and y = 14 when x = 8, find y when x = 7.

16

q varies inversely as r. If q = 5 when r = 2, calculate the value of q when r = 4.

2.5

In an electric circuit, the current varies inversely as the resistance. The current is 40 amps when the resistance is 12 ohms. Find the current when the resistance is 20 ohms.

24

x is inversely proportional to y². If x = 4 when y = 3. calculte the value of x when y = 1.

36

If y varies inversely as x, and y = 23 when x = 8, find y when x = 4.

46

Time varies inversely as speed if the distance is constant. A trip takes 4 hours at 80 km/h. How long does it take at 64 km/h?

5

p is inversely proportional to the √y. If p = 1.2 when y = 100, calculate the value of p when y = 4.

6

The number of hours required to do a job varies inversely as the number of people working. It takes 8 hours for 4 people to paint the inside of a house. How long would it take 5 people to do the job?

6.4

If z varies inversely as x² , and z = 9 when x = 2/3 , find z when x = 5/4.

64/25

t is inversely proportional to x². It t = 36 when x = 2, find the value of x when t = 3.

x = 16