To draw a heart, one would be choosing 1 card of 13 possible hearts, and 0 from the remaining 39 non-hearts. With respect to the entire deck, one would be choosing 1 card from 52 total cards. So the probability of drawing a heart is
When Michelle replaces the card, the deck returns the normal, so the probability of drawing any card from a given suit is the same,
. In other words, drawing a spade is independent of having drawn the heart first.
So the probability of drawing a heart, replacing it, then drawing a spade is
.
When Michelle replaces the card, the deck returns the normal, so the probability of drawing any card from a given suit is the same,
So the probability of drawing a heart, replacing it, then drawing a spade is