Aptitude - Odd Man Out and Series - Discussion

Find out the wrong number in the series.

4. 

445, 221, 109, 46, 25, 11, 4

[A]. 221
[B]. 109
[C]. 46
[D]. 25
[E]. 11

Answer: Option C

Explanation:

Go on subtracting 3 and dividing the result by 2 to obtain the next number.

Clearly, 46 is wrong.


Laxmi said: (Nov 17, 2010)  
series is wrong....think so

if wrong number is 46

it should be 445,221,109,53,46(45),21,9,3...

Thiyagu said: (Dec 16, 2010)  
it's 46

Nagendramurthy said: (Jun 17, 2011)  
Let me explain ..

445-3=442
442/2=221

221-3=218
218/2=109

109-3=106
106/2=53

53-3=50
50/2=25

25-3=22
22/2=11

11-3=8
8/2=4


So after 109 it should be 53.. in the given series it is 46 so

Have a nice day..!

Ammu said: (Jan 26, 2012)  
Nice explanation by Mr. Nagendramurthy. Thanks.

Priyanka said: (Jan 24, 2013)  
4*2+3=11
11*2+3=25
25*2+3=53 ------------ 46 which is an wrong series.
53*2+3=109
109*2+3=221
221*2+3=445

You might can understand this.

Satya said: (Jan 9, 2014)  
I had solved this problem like this.
Starting from the end.

4.
4+7=11,
11+14=25,
25+21=46,
46+28=74. So 109 is wrong.

Can anybody say whether the way is correct are not? and why?

Adesh said: (Mar 6, 2014)  
Yes 109 is wrong because 74* 35=2590 which is not the next number in the given series?

Bob said: (Nov 21, 2014)  
Hi but how did you find that it must be subtracted by 3 and multied by 2, seeing the question ? can any one help please.

Srinithi said: (Jun 26, 2015)  
Its really a tough question. Could not judge the way in which the series is written?

Albert said: (Apr 4, 2016)  
Very tough to find the answer.

Viji said: (Sep 21, 2016)  
Good explanation, thank you @Nagendramurthy.

Raju Rockzz said: (Sep 26, 2016)  
Super explanation @Nagendramurthy.

Apoorv said: (Dec 7, 2016)  
Sum every digit of every number in the series.

4 5 1 1 7 2 4. There's anyhow increase and decrease in the difference of number. Except 1 at the 4th place. Which corresponds to 46!

Kamlesh said: (Jun 20, 2017)  
The general form of the series is sigmal of GI (n\2) -1 put n=445 you will get 222.5 but GI of 222.5 is 222 subtract 1 from it you will get 221 and then put 221 on the series and so on.

B.M.Aakash said: (Jul 31, 2017)  
Good explanation. Thank you all.

Lakshu said: (Aug 15, 2017)  
We can simply do that:

445-221 = 224
224/2 = 112

221-109=112
112/2 = 56

109-46 = 63, So 46 is the wrong answer.

Akhil said: (Jun 4, 2018)  
4+7=11, 11+14=25, 25+28=53, 53+56=109,

Start adding with 7 then after 7*2, then the answer with 2. That's it.

Nandhajhon said: (Dec 12, 2018)  
Well explained, thanks, @Akhil.

Kannu said: (May 4, 2019)  
It should be 53.

Dhara said: (May 31, 2019)  
4.

I solved the question in this way.

4+7 = 11,
11+14 = 25,
25+21 = 46,
46+28 = 74.

So, 109 should be wrong.

I am right, Can anyone tell me?

Kamali said: (Jun 21, 2019)  
It could be cracked easily when solved from right to left.

Multiplying 2 and adding 3 to the multiplied result.

(4*2)+3 = 11.
(11*2)+3 = 25.
(25*2)+3 = 53.
(53*2)+3 = 109.
(109*2)+3 = 221.
(221*2)+3 = 445.

So, 46 is the wrong answer.

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