Y and x have a proportional relationship, and y = 25 when x = 60. What is the value of x when y = 30?

a. 25

b. 36

c. 50

d. 72

The equation governiong this relationship is y = kx. Since y = 25 when x = 60,

25 = 60k, and k = (5/12). Thus, the equation is y = (5/12) x.

If y = 30, then 30 = (5/12) x. Mult. both sides by 12/5 to obtain the value of x:

(12/5) (30) = 360/5 = 72