Aptitude - Odd Man Out and Series - Discussion

Discussion Forum : Odd Man Out and Series - Find Wrong No. (Q.No. 15)
Directions to Solve
Find out the wrong number in the series.

15.
3, 7, 15, 27, 63, 127, 255
7
15
27
63
127
Answer: Option
Explanation:

Go on multiplying the number by 2 and adding 1 to it to get the next number.

So, 27 is wrong.

Discussion:
12 comments Page 2 of 2.

Grace said:   1 decade ago
3+4 = 7.
7+8 = 15.
15+16 = 31.
*31+32 = 63.
63+64 = 127.
127+128 = 255.
255+256 = 511.

Here the series we are adding is 4,8,16,32,64,128,256....so on.

Hence 27 is the only wrong answer.

Major sandhu said:   1 decade ago
4-1 = 3.
8-1 = 7.
16-1 = 15.
32-1 = 31.


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