Which of the following numbers will replace the question mark (?) in the given series?
239, 274, 309, 354, 399, 454,?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 509.
239 + 35 = 274; 274 + 35 = 309; 309 + 45 = 354; 354 + 45 = 399; 399 + 55 = 454; 454 + 55 = 509