Question

P varies directly as Q and inversely as four times the cube root of R.if p=16,Q=8 and R=0.015,find R in terms of P and Q

Answer 1

P = k Q / [4 R^(1/3) ]
4 R^(1/3) = k Q/P
R^(1/3) = k Q / 4P
R = k^3 (Q/P)^3/64
.015 = k^3 (8/16)^3 / 64
.015 = k^3 /(8*64)
k^3/64 = .12
R = 0.12 (Q/P)^3

Answer 2

so, R varies directly as the cube of the ratio of Q and P.

:-)