There are eight numbers, the average is 7.5, the first five numbers are 8.8, the last four numbers are 9.5, what is the fifth number That 7.5 is the average of those eight numbers

There are eight numbers, the average is 7.5, the first five numbers are 8.8, the last four numbers are 9.5, what is the fifth number That 7.5 is the average of those eight numbers

8.8×5+9.5×4-7.5×8=22