Direct Proportion problem

If y = kx, where k is a constant such that x = 5 when y = 1/3, what is the value of x when y = 12?

A. 36/5
B. 15/12
C. 180
D. 12/15


First find the value of k: Using the known y and x-values, we have 1/3 = 5k, making k = 1/15. When y = 12, we have 12 = (1/15)x, making x = 180. The correct choice is (C).

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