Suppose one card is selected at random from an ordinary deck of 52 playing cards.

Question

Let

A= event a diamond is selected
B=event a club is selected

Determine P(A|(not B))

DrBob said it is 1/3

but how did he get it?
I keep getting answer

1 or 21/26

Answer 1

If you eliminate the 1/4 of the cards that are clubs, one third of what is left are diamonds.