Number Series Q17

17.	Look at this series: 80, 10, 70, 15, 60, ... What number should come next?
	A. 20 B. 25 C. 30 D. 50

Answer: Option A

Explanation:

This is an alternating addition and subtraction series. In the first pattern, 10 is subtracted from each number to arrive at the next. In the second, 5 is added to each number to arrive at the next.