Question

Which number should come next in the series? 13, 57, 911, 1315, 1719?

Answer 1

Solution,

Finding;

Difference between each number

1719-1315=404

1315-911=404

911-57=854

57-13=44

Here,4 is being added to both digits of the number. So the next number will be 17+4=21 and 19+4=23 which is 2123. So the next number to this series will be 2123.

Explanation:

Hope it helped you.

Answer 2

2123

like 1+4=5

3+4=7

Explanation:

All odd numbers beginning from one, in a series.

Also: Starting with 13, add 4 to each digit separately, and continue adding 4 to the result.