The average weight of Kiran, Mahesh and Ram is 46 kg. If the average weight of Kiran and Mahesh be 40 kg and that of Mahesh and Ram be 47 kg, then the weight of Mahesh (in kg) is:

Correct option is C

Given:
Average weight of Kiran, Mahesh, and Ram = 46 kg
Average weight of Kiran and Mahesh = 40 kg
Average weight of Mahesh and Ram = 47 kg
Solution:
Let weights of Kiran, Mahesh, and Ram be K, M, and R respectively.
​$$\frac{K + M + R}{3} = 46 \implies K + M + R = 138 .............(1)\\\ \\ \frac{K + M}{2} = 40 \implies K + M = 80..................(2) \\\ \\ \frac{M + R}{2} = 47 \implies M + R = 94 ...............(3)\\\ \\$$​​
Adding equation 2 and 3
​$$K + M + M + R = 80 + 94 = 174 ...............(4)$$​​

Subtract 4 from 1
(K + M + M + R) - (K + M + R) = 174 - 138 
M = 36 
Mahesh's weight is 36 kg.