Logical Reasoning - Number Series - Discussion

Find the number that fits somewhere into the middle of the series. Some of the items involve both numbers and letters

4. 

Look at this series: 70, 71, 76, __, 81, 86, 70, 91, ... What number should fill the blank?

[A]. 70
[B]. 71
[C]. 80
[D]. 96

Answer: Option A

Explanation:

In this series, 5 is added to the previous number; the number 70 is inserted as every third number.

Jaiveer said: (Jan 18, 2011)  
I could not understand pls explain it once again in simple terms.

Nikunj said: (Feb 11, 2011)  
70 is constant for every series.

Ami said: (May 5, 2011)  
How ? perhaps correct answer is 77 ?

Bhagyasree said: (Aug 14, 2011)  
77 is wrong ans once think. Apply your logic to all the numbers it will not work.

Anirudh said: (Aug 25, 2011)  
Dear friends,

Today I had a doubt on one of the series. Shall you provide the answer for it.

The sequence is 3, 4, 6, 8, 12, 14, ?

Ankit said: (Aug 27, 2011)  
Please explain it once again in simple terms.

Kalpana said: (Sep 13, 2011)  
70, 71, 76, __, 81, 86, 70, 91, ...

this is our question, split the question as


70,71,76

--,81,86

70,91,...

for every first column 70 will be constant
then for second column 71, 71+10, 81+10

therefore 70 is the answer.

Garima Gupta said: (Sep 22, 2011)  
Very simple 70 is repeting after every two series, thus I hope 70 is the right answer
70, 71, 76, __, 81, 86, 70, 91,

Isha said: (Nov 15, 2011)  
@Anirudh- 3, 4, 6, 8, 12, 14, ?.. ans is 18,20,24.....

concept is simple-- its prime no. + 1
so here it is
(2+1) (3+1) (5+1) (7+!) (11+1) (13+1) ..(17+1) (19+1) (23+1)..n so on...

Archana said: (Feb 2, 2012)  
Why is 70 taken as a constant number here?

Anish said: (Jun 11, 2012)  
70 is const. As it keeps on just repeating. It's the logic behind. Afterall it's logical reasoning test.

Omniscient said: (May 12, 2013)  
@Anirudh.

The answer to series is 3, 4, 6, 8, 12, 14, 24, 22, 48, 32...

It goes as follows 3*2=6, 6*2=12, 12*2=24. And 4+4=8, 8+6=14, 14+8=22, 22+10=32.

Ajay said: (Jun 5, 2013)  
3, 4, 6, 8, 12, 14, ?..

There are two diffrent series. Its 3, 6, 12,..24...48(3*2, 6*2, 12*2,... Logic).

4, 8, 14...(4,4+4, 4+4+6, 4+4+6+8, 4+4+6+8+10...Logic).

4, 8, 14, 22, 32 ..

Answer 3, 4, 6, 8, 12, 14, 24, 22, 48, 32..

Ramkumar said: (Jun 8, 2013)  
Hai @Anirudh.

Here 3, 4, 6, 8, 12, 14, ?

It is a series of: prime no.(2 3 5 7 11 13 17 19.....) + 1.

So next prime no: 17.

Then: 17+1=18.

Yadavji said: (Oct 9, 2013)  
There is no logic behind why 70 has taken as constant you have to assume it by your reasoning skill.

Ravi said: (Oct 17, 2014)  
I think the answer should be 96 then the next number will be 70 as it is constant after 2 digits.

Kinkaradhikary said: (Jul 31, 2015)  
70, 71, 76.
70, 81, 86.
70, 91, .

Answer: 70+0=70.

71+10=81.
76+10=86.

Correct answer 70.

M.Mareeswari said: (Sep 25, 2015)  
70 71 76 ____ 81 86 70 91.

The answer is:

71 + 5 = 76.

81 + 5 = 86.

91 + 5 = 96.

Different number is 5. 5 is add the next number but the 70 is common number. So the correct answer is 70 friends.

Kirubarani said: (Aug 22, 2016)  
The answer is 70 which is the constant for the given series.

Kirubarani said: (Aug 22, 2016)  
The answer is 70 which is the constant for the given series.

Tushar said: (Sep 22, 2016)  
This nmber is interpolated number so, every third number is 70.

Sittam said: (Oct 5, 2016)  
I also can't understand. Please help me.

Mahe said: (Feb 12, 2017)  
The correct series is;

70,71,76
70,81,86
70,91,96.

Surya said: (Jun 25, 2017)  
70 because every 3 number interval.

Prince Dholakiya said: (Jul 28, 2017)  
70 , 70 + 1 = 71 , 71 + 5 = 76 | 70,71,76 .
70 , 70 + 11 = 81 , 81 + 5 = 86 | 70,81,86.
70 , 70 + 21 = 91 , 91 + 5 =96 | 70,91,96.

Ritu said: (Aug 31, 2017)  
1, 9, 12, 76, 81, ?

Solve this.

Arulmurugan J said: (Oct 1, 2017)  
1 9 12 76 81 297
+2'3 +3 +4'3 +5 +6'3

It is 2 cube and so on.

Kinjal said: (Nov 15, 2017)  
Just because 70 is constant, it doesn't apply that logical answer should be 70.

Actually the question itself isn't logical.

The correct series should be 70, 71, 76, 80, 81, 86, 90, 91, 96...and so on.

Bhargavi said: (Jan 21, 2018)  
the question is 70 71 76 -- 81 86 90 91.
see the difference between 70 71 & -- 81 & 90 91 the difference is 1.
If you see the 71 76 & 81 86 &91 96 the difference is 5.
If you see the 76 -- & 86 90 the difference is 4.
So this pattern follows the 1 5 4 series.
So the answer be 80. and not the 70.

Sooraj said: (Aug 12, 2018)  
The matrix series is

70, 70, 70.
71, 71, 71.
76, 86, 96.

Akshay Gupta said: (Jun 24, 2019)  
I think answer should be 60 because the logic is:

+1 + 5 - 21 + 1 + 5 -21.

Dkaj said: (Jul 17, 2019)  
96 is the right answer.

Suren said: (Aug 10, 2019)  
Simple.. No need to think more.

Here shortest thing:
70,71,76,70,81,86,70,91,96,70,101,106,70,111,116,70.......so on...

Think about this series.. Just see where where 70 occurs.

Abhinaw Anand said: (Mar 25, 2020)  
If 5 is added then how 71 came as a second number.

Shivam said: (Jun 2, 2020)  
@Abhinaw.

5 is not added to 70, 5 is added to other numbers but 70 is repeating after every two numbers.

Ganesh Singha said: (Jun 30, 2021)  
80 is the correct answer.

Sanamdeep Singh said: (Aug 31, 2021)  
@Ganesh.

It's 70 as it's repeated after every two numbers.

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