A vessel full of pure acid contains 10 litres of it, of

A vessel full of pure acid contains 10 litres of it, of which 2 litres are withdrawn. The vessel is then filled with water. Next 2 litres of the mixture are withdrawn, and again the vessel is
filled up with water. The ratio of the acid left in the vessel with that of the original quantity is

Quantity of remaining acid = Initial quantitiy

	1 −	Quantity taken out		ⁿ
		Total initial quantity

= 10		1 −	2		²	= 10 ×		4		²
			10					5

= 10 ×	4	×	4	=	32	litres
	5		5		5

Required ratio =	32	: 10
	5

= 32 : 50
= 16 : 25