Medium
The average of 5 numbers is 18. If one of the numbers, 12, is removed, what is the average of the remaining numbers?
Explanation
Explanation
Step 1: Sum of the 5 numbers = average × count = 18 × 5 = 90.
Step 2: After removing 12, the sum = 90 − 12 = 78.
Step 3: Number of remaining values = 4.
Step 4: New average = 78 ÷ 4 = 19.5.
Step 5: Reasonable check: 12 was below the old average, so removing it should raise the average above 18 ✓.
Answer: 19.5.
PRO TIP
Re-check your working by substituting the answer back into the original question.