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

2. 

Look at this series: 664, 332, 340, 170, ____, 89, ... What number should fill the blank?

[A]. 85
[B]. 97
[C]. 109
[D]. 178

Answer: Option D

Explanation:

This is an alternating division and addition series: First, divide by 2, and then add 8.

Sathesh said: (Sep 23, 2010)  
How is possible 178?

Bakiya said: (Sep 28, 2010)  
Yes, how its possible. I think ans is wrong. The correct answer is 85. 170/2=85 then add 4.

Chinna said: (Nov 24, 2010)  
in the above split it into 3 parts each part contains 2 nos...
in the each part the 1st no is the double of the 2nd no...
that is
664=2*332
340=2*170
178=2*89

Saurabh said: (Jan 16, 2011)  
first divide by 2 and then add 8 it is clearly written

664/2=332
332+8=340
340/2=170
170+8=178

Satish said: (Jun 7, 2011)  
Thanks saurabh ji.

Manikandan said: (Jul 16, 2011)  
Take the 2nd, 4th and 6th numbers. Odd position=even position*2. For this sum it ll work as simple as that.

Reet said: (Sep 6, 2011)  
I think i can find a easier way..

664-332=332
340-170=170

So in the case of 89. We must have to do (89+89)= 178

So, only thats why it can continue the series like

178-89=89

Hope i can help you..

Rahul said: (Sep 24, 2011)  
170*2=340
332*2=664
so
89*2=178 ans

Kenneth Tombing said: (Apr 6, 2012)  
The pattern is reversed in this case. Its easy if calculated from the end.

Neetu said: (Apr 28, 2012)  
I agree with kenneth we have to look form both the ends from reverse way we can see the previous no. of last the no. will be the double of it.

Karamat Subhani said: (Apr 28, 2013)  
If 664/340 = 1.952.

Similarly 332/170 = 1.952.

And then 340/178 = 1.952.

In this way ratio will be same and so we can say 178 is correct answer.

Mihir said: (Dec 18, 2013)  
1> 664/2 = 332-> 2nd number.

2> 340/2 = 170-> 4th number.

3> 89*2 = 178 (5th no) == 178/2 = 89-->6th no.

Sam said: (Sep 26, 2014)  
I think the correct answer is 85 because the second number on the series from left to right 332 is less than the third number which is 340. If the same rule is applied from right to left, then 85 is the best answer.

Uma said: (Apr 16, 2015)  
664-332 = 332.
340-332 = 8.
340-170 = 170.
170+8 = 178.
178-89 = 89.
178-8 = 170.
170-89 = 81.
81+8 = 89.

Buddy said: (May 29, 2015)  
It is correct.

664/2 = 332.
332+8 = 340.
340/2 = 170.
170+8 = 178.
178/2 = 89.
89+8 = 97.

It goes on...answer is 178.

M.Mareeswari said: (Sep 25, 2015)  
332+332 = 664.

170+170 = 340.

89+89 = 178.

The correct answer is 178. So it is correct.

Nutan said: (Nov 13, 2015)  
664/2 = 332.
332+8 = 340.
340/2 = 170.
170+8 = 178.
178/2 = 89.

Then correct answer is 178.

Samsher said: (Mar 14, 2016)  
170/2 = 85+4 = 89.

Aviral said: (Jul 13, 2016)  
664/2 = 332 + 8 = 340.
340/2 = 170 + 8 = 178.
178/2 = 89 + 8 = 97.

Nagesh Badole said: (Jul 22, 2016)  
664/2 = 332 + 8 = 340.
340/2 = 170 + 8 = 178/2 = 89.

So, the answer is 178.

Shrinath Keni said: (Sep 11, 2017)  
Correct answer is 97.

Just add all the numbers. The answer will be alternate 7 and 8.

Chandu said: (Oct 11, 2017)  
Answer is 178. I agree.

Jayeeta said: (May 8, 2018)  
Thank you @Saurabh.

Abhijit said: (Jul 27, 2018)  
664-332=332.
340-170=170.
therefore the difference should be same thus;
178-89=89.

Hence the answer is 178.

Adhul said: (Mar 19, 2019)  
Yes, the answer is 85 (i.e 170/2).

Sachin Kumar said: (Aug 17, 2019)  
The successor number is the half of the predecessor. So, choose from the option which is double of the successor of the blank given i.e 178 is double of 89.

Vamsi said: (Mar 11, 2020)  
I Agree that answer:
664, 332, 340, 170, ____, 89

After 2 number multiply by 2,
Like 332*2 = 664.
170 *2 = 340.
89*2 = 178 So the answer is 178.

Akash Kumar said: (Jun 1, 2020)  
664/2 = 332.
340/2 = 140.
89*2 = 178.

Gautam said: (Oct 5, 2020)  
664, 332, 340, 170, ___, 89.

89 * 2 = 178,
170 * 2 = 340,
332 * 2 = 664.

Saranya. R said: (Dec 5, 2020)  
664, 332, 340, 170, ___, 89.
664/2 = 332,
332+8 = 340,
340/2 = 170,
170+8 = 178,
178/2 = 89.

Ali said: (Dec 5, 2020)  
Solution:

664/332 = 332 then 332+8.
340/2 = 170 + 8 = 178 => answer.

Post your comments here:

Name *:

Email   : (optional)

» Your comments will be displayed only after manual approval.