Question

Suppose y varies directly with x, and when y is 16, x is 9. Write the direct variation equation for the data and find y when x is 16.

Answer 1

Suppose y varies directly with x ----> y = kx, where k is a constant
when y = 16, x = 9
16 = 9k
k = 16/9, so we know
y = (16/9)x
when x = 16
y = (16/9)(16) = 256/9

checking:
16/9 = y/16
9y = 16*16
y = 256/9