# Aptitude - Odd Man Out and Series - Discussion

Discussion Forum : Odd Man Out and Series - Find Wrong No. (Q.No. 9)

*Directions to Solve*

Find out the wrong number in the series.

9.

40960, 10240, 2560, 640, 200, 40, 10

Answer: Option

Explanation:

Go on dividing by 4 to get the next number.

So, 200 is wrong.

Discussion:

8 comments Page 1 of 1.
Ravi said:
4 years ago

40960 = 64^2 * 10.

10240 = 32^2 * 10.

And so on but 200 can't be written like this.

So 200 is the answer.

10240 = 32^2 * 10.

And so on but 200 can't be written like this.

So 200 is the answer.

Niharika said:
7 years ago

From the last term of the series: (consider " * " as "to the power of").

10 x 2 * 0 = 10

10 x 2 * 2 = 40

10 x 2 * 4 = 160(not 200 which is given)

10 x 2 * 6 = 640

10 x 2 * 8 = 2560

10 x 2 * 10 = 10240

10 x 2 * 12 = 40960.

10 x 2 * 0 = 10

10 x 2 * 2 = 40

10 x 2 * 4 = 160(not 200 which is given)

10 x 2 * 6 = 640

10 x 2 * 8 = 2560

10 x 2 * 10 = 10240

10 x 2 * 12 = 40960.

Gowri rudra said:
8 years ago

According to other procedure 640 is also one of the answer.

Satya said:
9 years ago

How to understand that we have to divide by 4?

Priyanka said:
9 years ago

10 40 200 640 2560 10240 40960

Multiply by 4,

10*4 = 40.

40*4 = 160.

160*4 = 640.

640*4 = 2560..... Instead of 160 there is 200. So answer is 200.

Blind method

----------------

Observer last two digits.. in series.

40960, 10240, 2560, 640, 200, 40, 10

60, 40, 60, 40, 00, 40, 10

So 10 is not in Answer option.

So 00 is the answer == 200 :).

Multiply by 4,

10*4 = 40.

40*4 = 160.

160*4 = 640.

640*4 = 2560..... Instead of 160 there is 200. So answer is 200.

Blind method

----------------

Observer last two digits.. in series.

40960, 10240, 2560, 640, 200, 40, 10

60, 40, 60, 40, 00, 40, 10

So 10 is not in Answer option.

So 00 is the answer == 200 :).

(2)

Akshay said:
10 years ago

It has perfect square and it multiply by 10. But in 10, 200, 10240.

It is not an perfect square. In option 10 and 10240 is not given so it has out of choice. Hence 200 is correct.

It is not an perfect square. In option 10 and 10240 is not given so it has out of choice. Hence 200 is correct.

Indhumathi said:
1 decade ago

No, answer is 200 because

40960/4 is 10240.

10240/4 is 2560.

2560/4 is 640.

640/4 is 160.

But here they give 200, see

160/4=40 next number will be correct,

So the answer is 200, here 200 is wrong.

40960/4 is 10240.

10240/4 is 2560.

2560/4 is 640.

640/4 is 160.

But here they give 200, see

160/4=40 next number will be correct,

So the answer is 200, here 200 is wrong.

Madhu said:
1 decade ago

The answer should be 640. Because when it divided by 4, it does net get the next number.

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