#math trivia #258 solution

The digits 2, 5 and 8 form an arithmetic progression because each successive pair has the same difference:  5-2 = 8-5 = 3.   The answers consist of the numbers with digits

  • 2 a b

where a-2 = b-a.   Alternatively, we have a = 2+d and b = 2+2d where d is the difference between consecutive digits.  It is clear that d must be between -1 and 3 so that a and b will be between 0 and 9.  The answers are thus:

  • 210
  • 222
  • 234
  • 246

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s