The mean of 8 numbers is 35. if a number is excluded then the mean is reduced by 3. Find the excluded number.

Given : Mean of 8 numbers = 35

⇒ Sum of 8 numbers = 35 × 8 = 280

Now, when a number is excluded the mean is reduced by 3

⇒ Mean of remaining 7 numbers = mean of 8 numbers - 3 = 35 - 3 = 32

⇒ Sum of remaining 7 numbers = 32 × 7 = 224

Hence, number excluded = sum of 8 numbers - sum of 7 numbers = 280 - 224 = 56