Question

Y varies jointly with w and z inversely with x. If y=36, when x=14, w=7 and z=8. Then what is y when x=20, w=16, and z=10?

Answer 1

y = kwz / x


36 = k*7*8 / 14 =  56k/14  = 4k

k  = 36 / 4  = 9 

so equation is y = 9wz/x

when x=20,w=16 and z=10:-

y= 9* 16*10 / 20  = 72