Average age of A and B is 30 years that of b and C is 32 years and the average age of C and A is 34 years the age of C is?

A: 33 years

B:34

C: 35                                     

D: 36

Solution: 

1. As average of A and B is 30 hence

                (B+C) /2=30 ~ A+B =60  ~ B=60 –A

2. And average og B and C is 32 hence

                (B+C) /2=32 ~ B+C=64 ~ C=64-B ~ C=-(60-A) 

                ~ C=4 + A

3. And Average of C and A us 34 hence

                (C+A )/2=32~ C + A= 68 ~ C=68-A

                 Add 2 and 3 

                C+C = ( 4+A) + ( 68-A ) ~ 2C=72 ~ C=36

                Hence the value of C is 36