The average of six consecutive odd numbers, in increasing order, is 42. If the next five consecutive odd numbers are included, then what is the average of all the numbers?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 47.
Let the six consecutive odd numbers are x, (x + 2), (x + 4), (x + 6), (x + 8) and (x + 10)
[x + (x + 2) + (x + 4) + (x + 6) + (x + 8) + (x + 10)]/6 = 42
⇒ 6x + 30 = 252 ⇒ 6x = 252 - 30 ⇒6x = 222 ⇒ x = 37
Numbers will be 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57.
Average = (37 + 39 + 41 + 43 + 45 + 47 + 49 + 51 + 53 + 55 + 57)/11
⇒ 517/11 ⇒ 47