Question

complete the series with explanation
1,6,21,56,___​

Answer 1

1+5=6

6+15=21

21+25=56

56+35=91

in this series

First no. is added by 5

Second no. is added by 15 means 5+10

Third no. is added by 25 means 15+10

so,

Fourth no. is added by 35 means 25+10

Hope it helps