Question:medium

In an office with 8 employees, the average rating of all employees is 30. The average rating of the top five employees is 38, and the average rating of the bottom three employees is 25. Which of the following is not possible?

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To check feasibility, verify that the sum of individual parts matches the total and that averages align. Always double-check when combining smaller groups.
Updated On: Nov 26, 2025
  • One of the top five employees has a rating of 50.
  • The lowest rating among the bottom three employees is 20.
  • The highest rating among the top five employees is 40.
  • One of the bottom three employees has a rating of 24.
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The Correct Option is C

Solution and Explanation

Total Ratings:

Total ratings for all employees:

\[ \text{Total} = 8 \times 30 = 240 \]

Top Five and Bottom Three Totals:

Total ratings for the top five employees:

\[ \text{Top Five Total} = 5 \times 38 = 190 \]

Total ratings for the bottom three employees:

\[ \text{Bottom Three Total} = 3 \times 25 = 75 \]

Verification of Totals:

Sum of ratings for all employees:

\[ \text{Sum of Top Five + Bottom Three} = 190 + 75 = 265 \]

This sum (265) exceeds the calculated total ratings of 240, indicating a discrepancy.

Analyze the Options:

(A) One of the top five employees has a rating of 50:

If one top employee's rating is 50, the remaining total for the other four is:

\[ 190 - 50 = 140, \quad \text{Average for four} = \frac{140}{4} = 35 \]

This scenario is plausible, as the remaining ratings are consistent with the data.

(B) The lowest rating among the bottom three employees is 20:

If one bottom employee's rating is 20, the remaining total for the other two is:

\[ 75 - 20 = 55, \quad \text{Average for two} = \frac{55}{2} = 27.5 \]

This scenario is plausible, as the calculated averages are consistent.

(C) The highest rating among the top five employees is 40:

If the highest rating among the top five is 40, the remaining total for the other four is:

\[ 190 - 40 = 150, \quad \text{Average for four} = \frac{150}{4} = 37.5 \]

This contradicts the given average of 38 for the top five, rendering this scenario impossible.

(D) One of the bottom three employees has a rating of 24:

If one bottom employee's rating is 24, the remaining total for the other two is:

\[ 75 - 24 = 51, \quad \text{Average for two} = \frac{51}{2} = 25.5 \]

This scenario is plausible, as it meets the stated conditions.

Thus, the correct answer is (C).

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