What is the next number? 2, 7, 8, 3, 12, 9

Question:- What is the next number? 2, 7, 8, 3, 12, 9

Answer: The correct option is 4.

This sequence obeys a rule which changes to another rule in every other step of the sequence. The rule for constructing the sequence for the first, third, fifth … entity is to add 5 to the preceding first, third, fifth … entity number. Therefore, 2 + 5 = 7, 7 + 5 = 12, and so, if the sequence continues the next odd-positioned number is 12 + 5 = 17. Now on the even position hence 2nd, 4th, 6th, the rule is subtracted by 4 from the previous even-numbered position. Thus, subtracting 4 from 8 gives 4, then subtracting 4 from 4 gives 0, and finally, subtracting 4 from 0 gives -4. The two rules are then as follows: first, the sequence increases to 5, then decreases to 10, and increases to 12. The other rule is that if the number is in an even position, then it increases to 5 From the above sequence, it can be noticed that the last number given 9, is in an even position hence applying the above rule we get the next number 4. Therefore 9-4 = 5 meaning 5 is the next number in the sequence.