##
##
###
+ ###
####
In the above addition all the digits were replaced by
"#".
Please restore the original numbers, given that in each column the digits form a valid arithmetic progression.
• Based upon a puzzle by Polish mathematician Marek Penshko.
I think these are the only solutions:
28 + 36 + 644 + 352 = 1060
28 + 36 + 744 + 552 = 1360
28 + 36 + 844 + 752 = 1660
74 + 63 + 652 + 441 = 1230
74 + 63 + 752 + 641 = 1530
That's based on the assumption that the constant difference in an arithmetic progression cannot be 0. If it can, there are several (possibly many?) more solutions.

Posted by tomarken
on 20140519 13:39:33 