In the number series 11, 13, 15, 17, the next term is _______. – UGC NET Question

The series consists of consecutive odd numbers, each 2 greater than the previous one. We see 11, 13, 15 and 17 with differences of 2 throughout. Adding 2 to 17 gives 19. Therefore, 19 is the next consecutive odd number and fits the pattern.

Option A:
Option A is 18, which is an even number and would break the sequence of odd integers. It also changes the difference from 2 to 1, so it cannot be correct.

Option B:
Option B is 20, another even number, and is 3 greater than 17. This disturbs both the parity and the constant difference. Thus, it does not maintain the pattern.

Option C:
Option C is 21, which is odd but lies 4 units above 17 rather than 2. That disrupts the simple increase by 2 seen in the earlier terms. Therefore, 21 is not appropriate.

Option D:
Option D equals 19, an odd number exactly 2 more than 17. The extended series 11, 13, 15, 17, 19 keeps the same difference and parity property. Hence, this option correctly continues the sequence.