Question

if 4/5 of water rank is filled n 1 hour, how time will be required to fill the rest of it ?

Answer 1

15 minute's will take
solution
let the time be=
$\frac{4}{5} x$

so,
4÷5 x = 60
$x = 60 \times \frac{5}{4}$
75 min
time take to fill the water =75-60
= 15