In the number series 5, 16, 33, 56, 85, the next term is _______. – UGC NET Question

The differences between consecutive terms are 11, 17, 23 and 29. These differences themselves form an arithmetic progression with common difference 6. Therefore the next difference should be 35. Adding 35 to the last term 85 gives 120, which maintains the constant step of 6 at the second level.

Option A:
Option A gives 116, implying a difference of 31 from 85. This would make the final increase between differences equal to 2 instead of 6, producing 11, 17, 23, 29, 31. Hence 116 does not preserve the consistent second-level arithmetic structure.

Option B:
Option B gives 120, implying a difference of 35 from 85. The difference sequence becomes 11, 17, 23, 29, 35, showing a uniform increment of 6 between gaps. This alignment at both levels makes 120 the correct next term.

Option C:
Option C gives 124, yielding a difference of 39 from 85. That would make the last jump among differences equal to 10, which distorts the pattern of adding 6 each time. Therefore 124 is not suitable.

Option D:
Option D gives 128, corresponding to a difference of 43 from 85. This further enlarges the final increment and deviates even more from the expected value. Thus 128 cannot be considered the correct continuation.