In following number series, two terms have been put within brackets. Choose the appropriate option - Find the wrong number in the series :7, 28, 63, 124, 215, 342, 511

Answer: B. 28

Clearly, the correct sequence is
(23 - 1), (33 - 1), (43 - 1), (53 - 1), (63 - 1), (73 - 1), (83 - 1).
.'. 28 is wrong and should be replaced by (33 - 1) i.e. 26.
Hence, the answer is (b).