Question

Write the next number in the series given below 3,7,15,31,63

Answer 1

127 is the next no....
3×2+1=7
7×2+1=15
15×2+1=31
so on.....

Answer 2

Next number in series is 127
As difference between 3 and 7 is 4, 15 and 7 is 8, 15 and 31 is 16, 31and 63 is 32.
So we double the difference to take out the next number