Question

A basket contains 12 black marbles, 14 red marbles and 12 green marbles. What is the probability of picking a black marble first then a red marble as replacement?

Answer 1

$Black\:marbles=12$

$Red\:marbles=14$

$\:Green\:marbles=12$

$Total\:marbles=38$

$P\left(picking\:black\:marble\right)=\frac{12}{38}$

$P\left(picking\:red\:marble\right)=\frac{14}{38}$

$\:P\left(picking\:green\:marble\right)=\frac{12}{38}$

Therefore, the probability of picking the first black marble and then the second red marble with replacement is:

$P\left(black\:marble\:then\:red\:marble\right)=\frac{12}{38}\times \frac{14}{38}=\frac{42}{361}$