Multiple choice

(\text{The average of 9 numbers is 30. The average of first 5 numbers is 25 and that of the last 3 numbers is 35. What is the 6th number?})

  1. 20

  2. 30

  3. 40

  4. 50
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total sum of 9 numbers = 9 × 30 = 270. Sum of first 5 numbers = 5 × 25 = 125. Sum of last 3 numbers = 3 × 35 = 105. The 6th number is isolated, so: 270 - 125 - 105 = 40.

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