Question

2. If y varies inversely as x and
y = 3 when x = 5, find x when y = 2.5

Answer 1

Explanation:

From the law of variation,

y <> 1/x, where <> is the constant of proportionality. Therefore

y = k/x where k is a constant

3 = k/5 and k = 15

To find x when y = 2.5(5/2)

Go back to the second equation

y = k/x

5/2 = 15/x

When you cross multiply

5x = 30.

Divide through by 5,

x = 6.