What is the average of the first 31 odd numbers?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 31.
The first 31 odd numbers are
1, 3, 5, ......31 th terms
We know that,
Sn = n/2 × [2a + (n - 1)d]
⇒ Sn = 31/2 × [2 × 1 + (31 - 1) × 2]
⇒ Sn = 31/2 × [2 + 30 × 2]
⇒ Sn = 31/2 × [2 + 60]
⇒ Sn = 31/2 × 62
⇒ Sn = 31 × 31
⇒ Sn = 961
We know that,
Average = Sum of observations/Number of observations
Average = 961/31 = 31