Question

A tin of oil was $\frac{4}{5}$ full when six bottles of oil were taken out and four bottles of oil were poured in, it was $\frac{3}{4}$ full. How many bottles of oil did the tin contain initially?

Answer 1

Suppose the x bottles can fill the tin completely
Then
$\frac{4}{5}x-\frac{3}{4}x=6-4$
$\frac{x}{20}=2$
$x=40$
$\therefore requirednoofbottles=40$