The average of eight consecutive odd numbers is 48. Find the sum of the fifth and seventh numbers.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 102.
Let the 8 consecutive odd numbers be 2n + 1, 2n + 3, 2n + 5, 2n + 7, 2n + 9, 2n + 11, 2n + 13, 2n + 15
According to the question;
⇒ 2n + 1 + 2n + 3 + 2n + 5 + 2n + 7 + 2n + 9 + 2n + 11 + 2n + 13 + 2n + 15 = 48 × 8
⇒ 16n + 64 = 48 × 8
⇒ 2n + 8 = 48
⇒ 2n = 40
⇒ n = 20
Required sum = 2n + 9 + 2n + 13 = 4n + 22
⇒ 4 × 20 + 22 = 102