Question

Z varries jointly as w and x and inversely as y and z = 2 when w = 6, x = 5 and y = 15

Answer 1

Answer:

Z varies directly with x and inversely with y when x=6, y=2, and z=15. What is "z" when x=4 and y=9?

If z varies directly with x then z=ax for some a independent of x .

If z varies inversely with y then z=by for some b independent of y .

We can combine these to say z=cxy for some c independent of x and y . If we assume there are no other variables then we seek a constant c .

If z=15 when x=6 and y=2 then 15=c62 so c=5 .

When x=4 and y=9 we therefore have z=5×49=209=22