The average of five consecutive even number is M. If the next five even numbers are also included, the average of ten numbers will be:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e M + 5.
| Understanding/Application |
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The average of 5 consecutive even number = M Sum of the 5 numbers = 5M Let the 1st number be x. |
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[x + (x + 2) + (x + 4) + (x + 6) + (x + 8) + (x + 10)]/5 = M 5x = 5M - 20 x = M - 4 Next 5 numbers are x + 10, x + 12, x + 14, x + 16, and x + 18. On putting the value of x in these next 5 numbers - M + 6, M + 8, M + 10, M + 12, M + 14 Thus, the average of 10 numbers = [5M + (M + 6) + (M + 8) + (M + 10) + (M + 12) + (M + 14)]/10 = (10M + 50)/10 = M + 5 |