Aptitude - Alligation or Mixture

Alligation:

It is the rule that enables us to find the ratio in which two or more ingredients at the given price must be mixed to produce a mixture of desired price.

Mean Price:

The cost of a unit quantity of the mixture is called the mean price.

Rule of Alligation:

If two ingredients are mixed, then

		Quantity of cheaper		=		C.P. of dearer - Mean Price
		Quantity of dearer				Mean price - C.P. of cheaper

We present as under:

C.P. of a unit quantity of cheaper C.P. of a unit quantity of dearer
(c)	Mean Price (m)	(d)
(d - m)		(m - c)

(Cheaper quantity) : (Dearer quantity) = (d - m) : (m - c).

Suppose a container contains x of liquid from which y units are taken out and replaced by water.

After n operations, the quantity of pure liquid =		x		1 -	y		n		units.
					x