Logical Reasoning - Number Series - Discussion
Discussion Forum : Number Series - Type 1 (Q.No. 6)
Directions to Solve
In each series, look for the degree and direction of change between the numbers. In other words, do the numbers increase or decrease, and by how much
6.
Look at this series: 21, 9, 21, 11, 21, 13, 21, ... What number should come next?
Answer: Option
Explanation:
In this alternating repetition series, the random number 21 is interpolated every other number into an otherwise simple addition series that increases by 2, beginning with the number 9.
Discussion:
45 comments Page 2 of 5.
PRAVEEN said:
1 decade ago
21 is the randomly executed and 9, 11, 13 digits are increased by the value 2, so the answer is 15.
Rincy said:
1 decade ago
If we add 21+9 = 32.
9+21 = 32.
21+11 = 34.
11+21 = 34 it increases by 2 so the next number should be 36 21+15=36.
So answer 15.
9+21 = 32.
21+11 = 34.
11+21 = 34 it increases by 2 so the next number should be 36 21+15=36.
So answer 15.
BHUMIT DOBARIYA said:
1 decade ago
ODD POSITION : 21 21 21 21.
EVEN POSITION : 9 11 13 15 (ADD 2).
EVEN POSITION : 9 11 13 15 (ADD 2).
Tanweer said:
1 decade ago
21-12 = 9.
21-10 = 11.
21-8 = 13.
21-6 = 15.
21-10 = 11.
21-8 = 13.
21-6 = 15.
Titus said:
1 decade ago
21-9=12
12+9=21
21-11=10
10+11=21
21-13=8
8+13=21
21-15=6
6+15=21
21-17=4
4+17=21
The numbers increase by 2 in ascending order. Therefore the answer is 15.
12+9=21
21-11=10
10+11=21
21-13=8
8+13=21
21-15=6
6+15=21
21-17=4
4+17=21
The numbers increase by 2 in ascending order. Therefore the answer is 15.
Pawan Sharma said:
1 decade ago
21-12 = 9.
21-10 = 11.
21-8 = 13.
21-6 = 15.
21-10 = 11.
21-8 = 13.
21-6 = 15.
Preeti said:
1 decade ago
9 +2 = 11.
11+2 = 13.
13+2 = 15.
11+2 = 13.
13+2 = 15.
Bhargavi said:
1 decade ago
In increasing order by adding +2 then,
9+2 = 11.
11+2 = 13.
13+2 = 15.
So answer is 15.
9+2 = 11.
11+2 = 13.
13+2 = 15.
So answer is 15.
Boga laxman said:
1 decade ago
21-9 = 12
9-21 = 12
21-11 = 10
11-21 = 10
21-13 = 8
13-21 = 8
21-15 = 6
So answer is 15.
9-21 = 12
21-11 = 10
11-21 = 10
21-13 = 8
13-21 = 8
21-15 = 6
So answer is 15.
Manoj said:
1 decade ago
21, 9, 21, 11, 21, 13.
21-----after 9, 11, 13.
13-11=2, 11-9=2.
Series on 2.
Then 13+2=15 answer.
21-----after 9, 11, 13.
13-11=2, 11-9=2.
Series on 2.
Then 13+2=15 answer.
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