The average of 9 numbers is 72. The difference between the highest and lowest number is 54. If the highest number is excluded, the average of the remaining 8 numbers drops by 3. What is the lowest number?
Show answer & explanation
Correct answer: A
Explanation
Given:
Number of numbers = 9
Average = 72
Largest − Smallest = 54
New average after removing the largest = 72 − 3 = 69
Formula:
Total sum = Average × Number
Sum of 9 numbers = 9 × 72 = 648
Sum of 8 numbers = 8 × 69 = 552
Largest number = 648 − 552 = 96
Smallest number = 96 − 54 = 42