the mean of five numbers is 30. if one number is excluded, their mean becomes 28. the excluded number is:

Mean of 5 numbers = 30

Sum of the 5 numbers = 30 X 5 = 150

Mean of 4 numbers = 28

Sum of the 4 numbers = 28 X 4 = 112

The excluded number = sum of 5 numbers - sum of 4 numbers = 150 - 112 = 38