Question

Suppose y varies inversely with x and that y=2 when x=8 What is an equation for this inverse variation?

A.y=8/2x
B. y= 2/8x
C. y= x/16
D. y= 16/x
Is the answer A?

Answer 1

answer is

D. y= 16/x

cause
y = k/x 2 = k/8 2(8) = k k = 16 y=16/x

Answer 2

D. y= 16/x

Explanation:

If y varies inversely with x then it means that y decreases at a foxed rate for every increase in x. Introducing the constant of proportionality k, we can say that

y = k/x

where y=2 when x=8 , then

2 = k/8

k = 16

hence y = kx becomes

y = 16/x