Answers

2015-04-30T18:10:50+05:30
Average of A and B = 18 years
So, (A+B)÷2 = 18
Now after three years and adding C,
(A+B+C)÷3 +3 = 22, Equation-{1}
So, (A+B+C+9)÷3 = 22
       A+B+C+9 = 66
       A+B+C = 57
       A+B = 57-C
So, Putting value of A+B in Equation 1,
(57-C)÷2 = 18
57-C = 36
So, C = 57-36 = 21
So, C will be 21 years old.
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