In a calculation Mohan found that the average of 4 numbers is 25 and on rechecking Sohan noticed that a number 15 is wrongly taken as 51. Find the correct average.

26 18 10 16

16

If 15 is taken as 51, then extra = 51 - 15 = 36 Total extra average = \(\frac{36}{4}\) = 9 Correct average = 25 - 9 = 16