7, 26, 63, 124, 215, 342, ?
ক
391
খ
421
গ
481
ঘ
511
সঠিক উত্তর: 511
The terms of the given series are (23 - 1), (33 - 1), (43 - 1), (53 - 1), (63 - 1), (73 - 1),.....So, missing term = (83 - 1) = (512 - 1) = 511.