Question

Suppose y varies inversely with x and y = 5 when x = 7

Part A) Write an equation that models the variation.
Part B) Find x when y = 140.

Please explain every step.

Answer 1

Explanation:

y ∝ 1/x

5 ∝ 1/7

5 = k * 1/7

5 = k/7

k = 5*7 = 35

140 ∝ 1/x

140 = k/x

140 = 35/x

x = 35/140 = 1/4 = 0.25

hence, when y = 140, x = 1/4 or 0.25