Rice worth ₹35 per kilogram and ₹38 per kilogram are mixed with a third variety in the ratio 2:1:2. If the mixture is worth ₹42 per kilogram, the price of the third variety per kilogram is:

Correct option is D

​$$\begin{aligned}&42 = \frac{(35 \times 2) + (38 \times 1) + (x \times 2)}{2 + 1 + 2} \\ &42 = \frac{(70) + (38 ) + ( 2x)}{5} \\ &42 \times 5 = {(70) + (38 ) + ( 2x)} \\ &210 = {(70) + (38 ) + ( 2x)} \\&2x = 210 - 108 \\&x = \frac{102}{2} = 51 \end{aligned}$$   

Thus, the price of third variety is ₹51.