Logical Reasoning - Number Series - Discussion

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"In the middle of difficulty lies opportunity."

- Albert Einstein

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

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 A

Explanation:

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

Bakiya said: (Tue, Sep 28, 2010 07:42:17 AM)

Yes, how its possible. I think ans is wrong. The correct answer is 85. 170/2=85 then add 4.

Chinna said: (Wed, Nov 24, 2010 06:56:58 AM)

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=2332 340=2170 178=2*89

Saurabh said: (Sun, Jan 16, 2011 12:01:36 PM)

first divide by 2 and then add 8 it is clearly written 664/2=332 332+8=340 340/2=170 170+8=178

Manikandan said: (Sat, Jul 16, 2011 02:04:45 AM)

Take the 2nd, 4th and 6th numbers. Odd position=even position*2. For this sum it ll work as simple as that.

Reet said: (Tue, Sep 6, 2011 11:33:29 AM)

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..

Kenneth Tombing said: (Fri, Apr 6, 2012 03:42:38 PM)

The pattern is reversed in this case. Its easy if calculated from the end.

Neetu said: (Sat, Apr 28, 2012 04:55:48 PM)

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.