Question

A tub is filled with a mixture of 2 miscible fluids P and Q in the proportion 5:3. When 16 litres of the mixture is drawn off and the tub is filled with same amonut of fluid Q, the proportion becomes P:Q=3:5. How many litres does the tub hold___

Answer 1

Let the tub contain 5x litres of P and 3x litres of Q. total = 8x litres of mixture. When are taken out, (8x-16) litres will be left

The mixture will now contain $\frac{5}{8}(8x-16)=5(x-2)$ litres of P and 3(x-2) litres of Q.

Given that 16 litres of Q are added.

Ratio is given as

$\frac{5(x-2)}{3(x-2)+16}=\frac{3}{5}$

Solving we get x-2=3 ; x=5

Tub will hold 8x = 40 litres