The average of numbers is . When the largest number is removed, the average of the remaining numbers is . When the smallest number is also removed, the average of the remaining numbers is . What is the difference between the largest and the smallest of the numbers?
Answer and explanation
Correct answer: C.
- Step 1: Calculate group sums: sum of all numbers is ; sum without the largest is ; sum without largest and smallest is .
- Step 2: Find the extreme values: ; .
- Step 3: Determine the difference: .
Answer
.
Why not the others: is the decrease in mean (); is the value of the smallest number itself; is the value of the largest number itself; is an arithmetic subtraction miscalculation ().
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