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.
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.
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.
Sreenivas said:
7 years ago
@All. According to me,
21 - 12 = 9.
9 + 12 = 21.
21 - 10 = 11.
11 + 10 = 21.
21 - 8 = 13.
13 + 8 = 21.
21 - 6 = 15.
15 + 6 = 21.
21 - 12 = 9.
9 + 12 = 21.
21 - 10 = 11.
11 + 10 = 21.
21 - 8 = 13.
13 + 8 = 21.
21 - 6 = 15.
15 + 6 = 21.
(14)
Abi said:
1 decade ago
Hi, it cab be easily solved.
1st, 3rd, 5th, 7th place no's are same
2nd,4h,6th place are adding 2
9+2=11
11+2=13
13+2=15
ans=15
1st, 3rd, 5th, 7th place no's are same
2nd,4h,6th place are adding 2
9+2=11
11+2=13
13+2=15
ans=15
Anand said:
1 decade ago
2nd, 4rd, 6th number are added +2 .
Hence answer is 15.
2nd number is 9 +2=11.
4th number is 11+2= 13.
6th number is 13+2=15.
Hence answer is 15.
2nd number is 9 +2=11.
4th number is 11+2= 13.
6th number is 13+2=15.
Akhilesh said:
1 decade ago
It is solved by another way i.e.
remove all alternate 21 and get differences between rest nos.
We'll get right answer i.e. B.
remove all alternate 21 and get differences between rest nos.
We'll get right answer i.e. B.
Rohan said:
1 decade ago
Can anyone solve this Equation?
2(L+B) = 180 -------------- 1.
L - B = 8 -------------- 2.
Find the value of L and B?
2(L+B) = 180 -------------- 1.
L - B = 8 -------------- 2.
Find the value of L and B?
Pusam Naveen Kumar said:
2 years ago
Here, the common no is 21 so leave it. And the series is;
9 + 2 = 11,
11 + 2 = 13,
13 + 2 = 15,
So, the answer is 15.
9 + 2 = 11,
11 + 2 = 13,
13 + 2 = 15,
So, the answer is 15.
(54)
Eerappa said:
8 years ago
The second digit is 9,
4th digit is 11.
so alternatively adding two numbers,
after 3 the next is 15.
9,11,13,15..
4th digit is 11.
so alternatively adding two numbers,
after 3 the next is 15.
9,11,13,15..
(4)
Abhay ide said:
9 years 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.
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