In the number series 160, 80, 40, 20, the next term is _______. – UGC NET Question

Each term is half of the previous one: 160÷2 = 80, 80÷2 = 40 and 40÷2 = 20. This shows a geometric progression with ratio 1/2. Halving the last term 20 gives 10. Therefore, 10 is the correct next term in the series.

Option A:
Option A is 5, which is half of 10 rather than half of 20. Using 5 directly after 20 would require dividing by 4, not by 2, and thus break the consistent ratio. Hence, 5 is not suitable.

Option B:
Option B is 12, which does not correspond to 20 divided by 2 and would introduce an inconsistent operation. There is no earlier hint of subtracting or adjusting by 8. Therefore, 12 cannot be correct.

Option C:
Option C is 15, which lies between 10 and 20 and does not represent half of the previous term. Choosing 15 would leave the ratio undefined and unclear. Thus, it does not follow the pattern.

Option D:
Option D equals 10, obtained by 20÷2 and preserving the halving process. The extended series 160, 80, 40, 20, 10 keeps the same geometric structure with ratio 1/2. This confirms that 10 is the right continuation.