Question

The average of five numbers is 12.4. the average of four of these numbers is 11. what is the value of the fifth number?

Answer 1

Take 4×11 that makes the answer 44
Then yake 5×12.4 and that is 62
Take 62-44
The answer is 18

Answer 2

average of 4 numbers is 11 so 11*4 = 44

average of 5 numbers is 12.4 so 12.4*5 = 62

the 5th number = 62-44 = 18