Solve the following variation problems completely.
a. If y varies directly as x, and y=28 when x=7 , (a) express y as a function of x;(b) find the value of y when x(6);(c) how is y affected if x is doubled? Tripled?

b. The weight of W of a body varies inversely as the square of its distance d from the center of the earth. If the radius of the earth is 3960 miles, how much would a 50-kg man weight 1000 miles above the surface of the earth?

Question

Solve the following variation problems completely.
a. If y varies directly as x, and y=28  when x=7 , (a) express y as a function of x;(b) find the value of y when x(6);(c) how is y affected if x is doubled? Tripled?

b. The weight of W of a body varies inversely as the square of its distance d from the center of the earth.  If the radius of the earth is 3960 miles, how much would a 50-kg man weight 1000 miles above the surface of the earth?