Tea worth Rs 126 per kg and Rs 135 per kg are mixed with a third variety in the ratio 1 : 1 : 2. If the mixture per kg will be: 

Since first and second varieties are mixed in equal proportions.
$\begin{array}{l}\text{ So, their average price }=₹\left(\frac{126+135}{2}\right)\\ =₹130.50\end{array}$
So, the mixture is formed by mixing two varieties, one at Rs.130.50 per kg and the other at say Rs.x per kg in the ratio 2:2, i.e., 1:1. We have to find x.
By the rule of alligation, we have:

$\begin{array}{l}\therefore \frac{\mathrm{x}-153}{22.50}=1\\ \Rightarrow \mathrm{x}-153=22.50\\ \Rightarrow \mathrm{x}=₹175.50\end{array}$