SOLUTION: The average age of 30 boys in a class is 13 years , 9 more boys whose average age is 15 years join the class. Find the average of the whole class?

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Question 891485: The average age of 30 boys in a class is 13 years , 9 more boys whose average age is 15 years join the class. Find the average of the whole class?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The average age of 30 boys in a class is 13 years ,
9 more boys whose average age is 15 years join the class.
Find the average of the whole class?
:
That is a total of 39 boys divided into two groups
Av = %28%2830%2813%29%2B9%2815%29%29%29%2F39
Av = %28%28390%2B135%29%29%2F39
Av = 525/39
Av = 13.5 av of the whole class