1. z varies directly as w and z = 50 when w = 40 , find the equation of variation. 2. m varies directly as n, if m = 3 when n=2, find m when n = 3 3. y varies inversely as x and y = 1/16 , when x = 8, find y when x = 17 4. y varies inversely as x and y = 8 when x = 18 , find the constant of variation