The arithmetic mean

Question

The arithmetic mean of a set of ninety numbers is 47. One-third of the numbers are increased by six. What is the mean of the new set.

 

 

This was a bit troubling for me

Please help,

And explain the steps of how to get there

Thank you!

Answer 1

N represents the sum of the 90 numbers.

47 = N / 90        definition of mean

4230 = N

4230 + (30)(6) = N₁    the new sum

4230 + 180 = N₁

4410 = N₁

4410 / 90 = ?