Hi

If y varies directly as x^3 and y =400 when x=10  400 = k*1000    k = 4/10 = 2/5

a. Find y in terms of x:   y = (2/5)x^3

b. Find y  when  x=5       y = (2/5)125 = 50

c.Find x when y=25 3/5     128/5 = 2/5x^3   x^3 = 64   x = 4 

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