Question

The average of 5 numbers is 27. If one number is excluded, the average becomes 25. The excluded number is:

• A. \(30\)
• B. \(35\)
• C. \(45\)
• D. \(25\)

Hint:

Whenever average and number of observations are given, first convert them into total sums using \[ \text{Sum}=\text{Average}\times\text{Number of Observations}. \] Then compare the sums to obtain the missing value.

Answer 1

The Correct Option is B

Concept: \[ \text{Sum}=\text{Average}\times\text{Number of Observations}. \]

Step 1: Calculate the sum of the 5 numbers. \[ 27\times5=135. \]

Step 2: Calculate the sum of the remaining 4 numbers. \[ 25\times4=100. \]

Step 3: Find the excluded number. \[ 135-100=35. \] Therefore, \[ \boxed{35} \] is the excluded number.