Answer
Assume that all 13 cards are hearts. Since 5 cards needs to be drawn, so
13! / 5! (13-5)!
= 13! / 5! 7!
= 1,287
There are 4 suits, so
Possible flushes = 4 x 1287 = 5,148
P(flush) = 5,148 / 2,598,960
= 0.002
Work Step by Step
As given in answer