Question

Please help me thank you

Answer 1

`\begin{cases} 8~blue\\ 2~red\\ 10~green \end{cases} \qquad \stackrel{\textit{sample space}}{8+2+10=20} \\\\[-0.35em] ~\dotfill\\\\ P(red)=\cfrac{2}{20}\implies P(red)=\cfrac{1}{10}\hspace{9em}P(blue)=\cfrac{8}{19}`

first off let's notice our sample space is just the total amount of marbles, so when we drew out the red one, there were 20 total, but but but, once we went ahead to get the blue one, there were no longer 20, because the one was out and it wasn't put back in the bag, not replaced, so our sample space changed to 20 - 1 = 19 when we drew out the blue one.

Now, p(red) AND p(blue), recall AND means product.

`\stackrel{ \textit{not replaced} }red)\implies \cfrac{1}{10}* \cfrac{8}{19}\implies \cfrac{8}{10}* \cfrac{1}{19}\implies \cfrac{4}{5}* \cfrac{1}{19}\implies \cfrac{4}{95}`