Respuesta :

sequence:                                      14    5    18    24    15    28    34
difference between each number:    -9   13    6      -9     13     6

The difference between each number goes -9 then 13 then 6 so the next number in the sequence would have difference of -9. Therefore the next number in the sequence would be 25. 
You add 10 to each number in the series of three. If you break the pattern into groups of three you will see 8-14-5 then 18-24-15 etc.

so 8+10=18+10=28, 14+10=24+10=34, 5+10=15+10=25,

it would be 25.