The mean of five number is 30. If one number is excluded their mean become 28. Find the excluded number.
Mean of 5 numbers = 30
Sum of the 5 numbers = 30 × 5 = 150
Mean of 4 numbers = 28
Sum of the 4 numbers = 28 × 4 = 112
The excluded number = sum of 5 numbers - sum of 4 numbers = 150 - 112 = 38