math
posted by rama .
A bag got mix up 6 pairs of shoes – 2 red, 2 blue, and 2 purple. Picking randomly, how many shoes must I pick before for sure that there is one matching pair in red or blue?
Ms Sue answered 4. Request for explanation please.

With 3 picks she could have gotten 1 red, 1 blue, and 1 purple shoe. On the 4th pick, she has to pick one of the colors she already had. Therefore, it will take 4 draws before she'd be sure she had a pair.

I just read it again  to see that you must have a matching pair in red or blue.
You'll need 5 picks instead of 4. 
Sue,
there are possibilities beyond what you may have quoted...did i misunderstand here?