Y varies jointly as x and √z. If y = 6 when x = 3 and z = 9, find y when x = 4 and √z = 3.6.

Y = kx√z where k is some constant

To find the value of k we plug in the given values of x, y and z:-

6 = k*3*√9

6 = k*3*3

9k = 6

k = 6/9 = 2/3

so the relation is y = (2/3) x√z

When x = 4 and √z = 3.6 we have:-

y = (2/3) * 4 * 3.6

= 9.6 Answer