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.
CHINNA...IIIT said:
1 decade 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:
7 years ago
@Akhilesh.
Thanks this is the simplest one. Thanks for the explanation.
Thanks this is the simplest one. Thanks for the explanation.
(3)
Rajini arunkumar said:
8 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)
Sahil suman said:
1 decade ago
It can also be done by.
9+2=11, 11+2=13, 13+2=15 answer is 15.
9+2=11, 11+2=13, 13+2=15 answer is 15.
Jhansi said:
9 years ago
Logic : 21 becomes constant and alternate number should add 2.
Swarnendu said:
9 years ago
21 remains interpolated and 2 is added to the number.
Muzaan ul aazeem said:
8 years ago
Adding and subtracting both we can use in descending or ascending.
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.
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.
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