Average of 50 numbers was calculated as 20 when three numbers, 26, 36 and 64 were wrongly read as 31, 46 and 59 respectively. What is the correct average?

26.2 19.8 20.2 24.4

19.8

Difference in sum due to wrong entry =( 28 + 36 + 64) - ( 31 + 46 + 59) = -8 Correct average = 20 - \(\frac{8}{50}\) = 19.84 = 19.8