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 2 of 5.
CHINNA...IIIT said:
2 decades ago
*It is done in another way i.e..
by using decreasing order
21-12=9
21-10=11
21-8=13
21-6=15
so, decrease the subtract number to one by one..2
by using decreasing order
21-12=9
21-10=11
21-8=13
21-6=15
so, decrease the subtract number to one by one..2
(3)
Bhagyalakshmi dayal said:
8 years ago
@Akhilesh.
Thanks this is the simplest one. Thanks for the explanation.
Thanks this is the simplest one. Thanks for the explanation.
(3)
Tannu said:
7 months ago
Yes, the answer is 15.
(2)
Ankit choudhari said:
2 weeks ago
The best answer for this question is;
21, 9, 21, 11, 21, 13, 21, ...
= 9 + 2 = 11.
= 11 + 2 = 13.
= 13 + 2 = 15.
21, 9, 21, 11, 21, 13, 21, ...
= 9 + 2 = 11.
= 11 + 2 = 13.
= 13 + 2 = 15.
(1)
Rajini arunkumar said:
9 years ago
21-12 = 9
9+12 = 21
21-10 = 11
11+10 = 21
21-8 = 13
13+8 = 21
21-6 = 15.
Why substracting 6 means, they subtracting adding like 10,8 so next even no.is 6 only.
9+12 = 21
21-10 = 11
11+10 = 21
21-8 = 13
13+8 = 21
21-6 = 15.
Why substracting 6 means, they subtracting adding like 10,8 so next even no.is 6 only.
(1)
Priyangsi said:
1 decade ago
ANS to you Rohan,
Given:
2(L+B) = 180.
= L+B = 180/2 = 90----------- 1.
And we have,
L-B = 8------------ 2.
On adding 1 and 2, we get,
= L+B+L-B = 90+8.
= 2L = 98.
= L = 98/2 = 49 (value of L).
And B = L-8 (From 2).
B = 49-8 = 41 (value of B).
So, answer => L = 49.
=> B = 41.
Given:
2(L+B) = 180.
= L+B = 180/2 = 90----------- 1.
And we have,
L-B = 8------------ 2.
On adding 1 and 2, we get,
= L+B+L-B = 90+8.
= 2L = 98.
= L = 98/2 = 49 (value of L).
And B = L-8 (From 2).
B = 49-8 = 41 (value of B).
So, answer => L = 49.
=> B = 41.
(1)
Swarnendu said:
10 years ago
21 remains interpolated and 2 is added to the number.
Malkeet singh said:
2 decades ago
Another method:
21 is coming after every different number.
If we add 2 with every different number in ascending order automatic give the result.
For example:
different no. 9+2=11
different no. 11+2=13
different no. 13+2=15 and so on.
21 is coming after every different number.
If we add 2 with every different number in ascending order automatic give the result.
For example:
different no. 9+2=11
different no. 11+2=13
different no. 13+2=15 and so on.
Saroj said:
2 decades ago
It is done in another way i.e..
by using decreasing order
11-9=2
13-11=2
15-13=2
so decrees the 2
by using decreasing order
11-9=2
13-11=2
15-13=2
so decrees the 2
Vivek srivastava said:
2 decades ago
It is difference of number are 2
so
21-9=12
21-11=10
21-13=8
and
12-2=10
10-2=8
8-2=6
so
21-6=15
This is the right answer solved by vivek Srivastava.
so
21-9=12
21-11=10
21-13=8
and
12-2=10
10-2=8
8-2=6
so
21-6=15
This is the right answer solved by vivek Srivastava.
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