A) 33 years
B) 43 years
C) 35 years
The average of A & B is
( A+B) /2 = 30 ⇒ A+B=60 ⇒ A= 60 – B —- (i)
( B+C)/2 = 64 ⇒B+C = 64 ⇒ B= 64 – C—- ( ii )
Putting the value of B in equation ( i )
⇒ A= 60 – 64 +C ⇒ A = -4 + C —– ( iii)
( C+A)/2 = 34 ⇒ C+A=68 ⇒ C = 68 – A —–(iv)
Putting the value of A from equation ( iii) to eq. (iv)
⇒ C= 68 +4 -C ⇒ C =36