# Aptitude - Odd Man Out and Series - Discussion

Discussion Forum : Odd Man Out and Series - Find Wrong No. (Q.No. 4)
Directions to Solve
Find out the wrong number in the series.

4.
445, 221, 109, 46, 25, 11, 4
221
109
46
25
11
Explanation:

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

Clearly, 46 is wrong.

Discussion:
23 comments Page 1 of 3.

Kartik said:   3 years ago
11 is the only one which is prime no. So the answer is option D.
(1)

Harshita said:   3 years ago
@Dhara.

Your way of solving the question is wrong because then the given series is proved wrong.

4+7=11.
11+14=25,
25+21=46,
46+28=74,
74+35=109,
109+42=251.

Hence the given solution is correct.
(2)

Kamali said:   4 years ago
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.
(2)

Dhara said:   4 years ago
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?

Kannu said:   4 years ago
It should be 53.

Nandhajhon said:   5 years ago
Well explained, thanks, @Akhil.

Akhil said:   5 years ago
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.

Lakshu said:   6 years ago
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.

B.M.Aakash said:   6 years ago
Good explanation. Thank you all.

Kamlesh said:   6 years ago
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.