How many pairs of positive integers, without regard to order, have a least common multiple of 540?
(In reply to One for column A, and one .. (spoiler?)
by Steve Herman)
....without regard to order:
One should count pairs e.g. 20*27, is one pair - not two.
Still I like your approach, just discount the 540,540 pair ,divide by 2 to get an a<b pair then add the symmetric pair and you get 53.
- which I believe is the correct answer.
I got 52 and do not have the time to find where is the miss.
Edited on December 22, 2014, 8:38 pm