The average of the first twelve multiples of 11 is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 71.5.
First multiple of 11 = 11
12th multi[ple of 11 = 11 × 12 = 132
Sum of n multiples of 11, Sn = (n/2)(first multiple + last multiple)
⇒ (12/2)(11 + 132)
⇒ 6 × 143 = 858
Now, average = 858/12 = 71.5