Question

A bag contains $7$ marbles: $3$ black, $2$ white and $2$ red. If you put your hand in the bag and draw out one marble, then find $P(notred)$?

Answer 1

Finding the probability of not getting a red marble

The event here is not drawing a red marble from the bag containing marbles.

There are a total of $7$ marbles in the bag that can be drawn.

So, the total number of outcomes is $7$.

There are $3$ black, $2$ white and $2$ red marbles in the bag that can be drawn.

So, the number of favorable outcomes is the number of black and white marbles,

$3+2=5$

The formula for probability is

$Probability=\frac{Numberoffavorableoutcomes}{Totalnumberofoutcomes}$

$\Rightarrow P(notred)=\frac{5}{7}$

Hence, the probability of not getting a red marble is $\frac{5}{7}$.