For any single draw,
\(\mathbb P(\text{white})=\dfrac6{42+6+8}=\dfrac6{56}\)
\(\mathbb P(\text{gray})=\dfrac8{42+6+8}=\dfrac8{56}\)
Drawing a white marble or a gray marble are disjoint events; only one of them can happen. So
\(\mathbb P(\text{white or gray})=\mathbb P(\text{white})+\mathbb P(\text{gray})-\underbrace{\mathbb P(\text{white and gray})}_0\)
\(\mathbb P(\text{white or gray})=\dfrac6{56}+\dfrac8{56}=\dfrac{14}{56}\)
Out of 224 draws, you should expect \(\dfrac{14}{56}\times224=56\) of the marbles to be either white or gray.
