Answer
$\frac{2}{7}$
Work Step by Step
The events are dependent because the marbles are not replaced
3 of the 7 marbles are yellow:
P(yellow)=$\frac{3}{7}$
4 of the 6 remaining marbles are red:
P(red after yellow)=$\frac{4}{6}$=$\frac{2}{3}$
P(yellow then red)=P(yellow) $\times$ P(red after yellow)
P(yellow then red)=$\frac{3}{7}$ $\times$ $\frac{2}{3}$
P(yellow then red)=$\frac{2}{7}$
