Logical Reasoning - Number Series - Discussion

Discussion Forum : Number Series - Type 2 (Q.No. 2)
Directions to Solve
Look carefully for the pattern, and then choose which pair of numbers comes next.

2.
8 11 21 15 18 21 22
25 18
25 21
25 29
24 21
22 26
Answer: Option
Explanation:
This is an alternating addition series, with a random number, 21, interpolated as every third number. The addition series alternates between adding 3 and adding 4. The number 21 appears after each number arrived at by adding 3.
Discussion:
66 comments Page 2 of 7.

Harpreet Singh said:   1 decade ago
21 is common after every 2 number. So

8 11 21 15 18 21 22...

8+3 = 11 21.
15+3 = 18 21.
22+3 = 25 21.

So answer is 25 21.

Saurabh said:   1 decade ago
Hi,

Random number is 21 and is repeated after two number.

3 is adding to 22 the result is 25 and 21 is repeated again.

Mehtab said:   8 years ago
There is a mistake in explanation. 21 is repeating as random number while 7 is added to each pair to get the new pair.

K Devraju said:   9 years ago
21 is Common in this Series.

So you can See,

=> 8 + 3 = 11.
=> 15 + 3 = 18.
=> 22 + 3 = 25.

Answer comes (25 21).

Milan Dheeraj said:   2 years ago
Skip 21
Add 3 and 4 gradually
8+3=11 (skip 21)
11+4=15.

15+3=18 (skip 21)
18+4=22.
22+3=25 (skip 21)
Ans : 25 21.
(28)

Hasan faraz said:   1 decade ago
Good question.

8 11 21 15 18 21 22
It is a sequence of adding 3, putting 21, adding 4 to the result of adding 3.

DIVAKAR .U said:   9 years ago
8 11 {21} = The difference is 3.

15 18 {21} = The difference is 3.

22 25 {21} = The difference is 3.

Praveen Reddy said:   1 year ago
8 +7 = 15.
11 + 7 = 18.
21 common.
15 + 7 = 22.
18 + 7 = 25.
21 common.
So, the answer is 25 21.
(28)

Sarveshwar said:   6 years ago
8+3=11,
11-21=10
10+3=13.

15-18=3,
18-21=3
3+3=6.

Then 13-6=7.
22+3=25, 25-4 = 21.
22,25,21.

Rama kant said:   9 years ago
8 + 7 = 15,
15 + 7 = 22,
11 + 7 = 18,
18 + 7 = 25,
21 is constant.

Every number add 7 except 21.


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