we have
marbles
3 red
2 blue
5green
7 yellow
total=3+2+5+7
total=17
2)draws a yellow marble replace it and then draws a blue marble
the probability of drawing a yellow marble is

since we replace the marble the total number of marbles keeps the same
then the probability of drawing a blue marble is

now the total probability of
draws a yellow marble replace it and then draws a blue marble is


