Fill in the missing number in the series.

2 3 6 15 ___ 630

Question

Fill in the missing number in the series.

2   3   6   15   ___   630

Accepted Answer

45 Looking at consecutive ratios: 3/2 = 1.5, 6/3 = 2.0, 15/6 = 2.5. The ratios increase by 0.5 each time. The next ratio should be 3.0, giving the missing term as 15 * 3 = 45. Then checking 630/45 = 14, which is the ratio to the final term. The ratios 1.5, 2.0, 2.5, 3.0 form an arithmetic sequence with common difference 0.5, supporting the answer 45.