top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

Which number should replace the question mark? 16, 2, 15, 4, 13, 7, 10, 11, 6, ?

+1 vote
5,624 views
posted Feb 23, 2017 by Anil Chaurasiya

Share this puzzle
Facebook Share Button Twitter Share Button LinkedIn Share Button

1 Answer

0 votes

Thanks for the query.

The series is comprised of two separate ones with the odd members and even members in different series.
The odd numbered members 16, 15, 13, 10, 6 is decreasing with a difference of -(d + 1), where d = 0 i.e., the common difference is -1, -2, -3 and so on.
The even numbered members 2, 4, 7, 11 are increasing with a difference of (d + 1), where d = 1 i.e., the common difference is 2, 3, 4, etc
Hence the 10th member of the series should be 11 + (4 +1) = 16

answer Feb 23, 2017 by Indranil Datta
...