Question

A. Write an equation that models the expression where y varies inversely with x.

b. If y = 20 when x = 4, solve for k.
c. Rewrite your equation from part a., subbing in the value for k that you solved for in part b.

Answer 1

y = k/x, k = 80, and y = 80/x

a.The best way to solve this problem is using reverse proportionality, in which two magnitudes x and y are inversely proportional when there is a constant k. If y varies inversely with x, then y = k/x

b. If y = 20 when x = 4, then k = (x)(y) -----> k = (4)(20) = 80

c. y = 80/x