T is inversely proportional to the cube of u. When u=5, t = 0.0096 find the value of u when t = 0.15

From the information given,

t α 1/u³

thus

t=k/u³

where k is the constant of proportionality

k=tu³

where

u=5, t=0.0096

then

k=5 (0.0096) = 0.048

hence

t=0.048/u³

thus the value of u when t=0.15 will be:

0.15=0.048/u³

u³=0.048/0.15

u³=0.32

u=³√0.32

u=0.684