The average would be the total amount divided by the 2 groups, so the answer would be 37.5 years old.
The fraction is 
Step-by-step explanation:
Let,
The denominator of fraction = x
Numerator of fraction = x-3
Fraction = 
According to given statement;
1 is added to the numerator, the value of the fraction becomes 3/4.

Using cross multiplication

Fraction = 
Keywords: fraction, division
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