Logical Reasoning - Number Series - Discussion

What is your confusion boss it is easy to get because hare to first number first 3 is added and then as third number interpolation would come and then what is there before interpolation number that would be added by 4 like this it will be go on.

8 11 [21] 15 18 [21] 22 25 [21] 29 32 [21] 36 39 [21] 43 46 [21] ....

Here 3, 4 is added alternatively and [21] injected as given below:

Inital = 8
8 + 3 = 11
********** [21]
11 + 4 = 15
15 + 3 = 18
********** [21]
18 + 4 = 22
22 + 3 = 25 <----- Required Answer
********** [21] <----- Required Answer
25 + 4 = 29
29 + 3 = 32
.........etc

Among all the above solution, I think Sundar is right.

Good explained by Sundar.

Thanks Sundar.

Great job sundar.

8,11,[21],15,18,[21],22,25,[21],29,32,[21]

1st no is 8,when 7 is added ,it gives 15 (4th number in series)
2nd no is 11 ,again when 7 is added,it gives 18(5th no in series)
21 is interpolated as every 3rd no.


4th no is 15 ,when 7 is added,it gives 22 (7th no)
5th no is 18,when 7 is added,it gives 25 (8th no)
again 21 is interpolated as 3rd no (here its 6th).


7th no is 22 ,when 7 is added,it gives 29 (10th no)
8th no is 25,when 7 is added,it gives 32 (11th no)
again 21 is interpolated as 3rd no (here its 9th).and so on.....

Really great, I can understand sundar's explanation thank you.

Actually it would be 25, 29. Adding 3 and alternate adding 4. So it should come 25, 29.

I am not able to understand it please explain it as a layman could understand.