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:
47 comments Page 4 of 5.
Muzaan ul aazeem said:
9 years ago
Adding and subtracting both we can use in descending or ascending.
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.
Preeti said:
1 decade ago
9 +2 = 11.
11+2 = 13.
13+2 = 15.
11+2 = 13.
13+2 = 15.
Jhansi said:
10 years ago
Logic : 21 becomes constant and alternate number should add 2.
M.RAGHURAM PGDM 1 said:
10 years ago
Take 21 alternatively and add 2 so, the answer is 15.
Shivam said:
1 decade ago
You see that the series is,
21 - 9 = 12.
Again after 9 have 21.
Again you see 2,
And again 21 - 9.
You see that 10, 10, 8, 8, 6, 6 series has follows.
21 - 9 = 12.
Again after 9 have 21.
Again you see 2,
And again 21 - 9.
You see that 10, 10, 8, 8, 6, 6 series has follows.
Abhay ide said:
1 decade ago
By adding the given numbers.
21 + 9 = 30.
21 + 11 = 32.
21 + 13 = 34.
21 + 15 = 36.
This increased by 2 numbers.
21 + 9 = 30.
21 + 11 = 32.
21 + 13 = 34.
21 + 15 = 36.
This increased by 2 numbers.
Sheenam said:
1 decade ago
Yes, 11 + 2 = 13.
13 + 2 = 15.
This is very easy question but my according this question is very confused.
13 + 2 = 15.
This is very easy question but my according this question is very confused.
Alisha said:
1 decade ago
21+0 = 21, 9+2 = 11, 21+0 = 21, 11+2 = 13, 21+0 = 21, 13+2 = 15.
Answer: 15.
Answer: 15.
A.G RAO said:
1 decade ago
The 21 is a referendums numbers every one should be show:
9+2 = 11, 11+2 = 13, 13+2 = 15.
So 15 is right answers nor essay answer.
9+2 = 11, 11+2 = 13, 13+2 = 15.
So 15 is right answers nor essay answer.
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