Which number comes next in this series: 154, 77, 81, 78, 39, 43, 40, ?
4 Answers

/2, +4, 3, repeat. 20 is next.

20
since this series consist of 3 nos i.e x , x+4,x+1
and the next sereis is generated by subtracting x1 from the first no of series i.e x
so 39(x1)=x
39x+1=x
x=20
so next series will be 20,24,21 ……..

yup, as above

/2, +4, 3
so answer is 20…………………