In a sequence of 12 consecutive odd numbers, the sum of the first 5 numbers is 425. What is the sum of the last 5 numbers in the sequence?

GATE 2014 · General Aptitude · Sequence Series · medium

Answer: The sum of the last 5 numbers is 495.

1. Set up sum of the first 5 terms: First 5 terms: a, a+2, a+4, a+6, a+8. Sum = 5a + (0+2+4+6+8) = 5a + 20. Given 5a + 20 = 425, so 5a = 405, a = 81.
2. Identify the last 5 terms: 12 consecutive odd numbers starting at 81: ..., term_8 = 81+14=95, term_9=97, term_10=99, term_11=101, term_12=103.
3. Compute sum of last 5 terms: Sum = (a+14)+(a+16)+(a+18)+(a+20)+(a+22) = 5a + 90 = 5*81 + 90 = 405 + 90 = 495.