# A box contains 5 red, 2 white, & 3 blue marbles. If a marble is selected at random, what is the probability that it is red or white?

May 3, 2018

$\frac{7}{10}$

#### Explanation:

Probability that it is red =$\frac{5}{10}$
Probability that it is white =$\frac{2}{10}$

So the probability that it is red or white =$\frac{5}{10} + \frac{2}{10} = \frac{7}{10}$

Another way

Probability that it is red or white is the same as it NOT being blue
Probability that it is blue =$\frac{3}{10}$, so the probability that it is NOT blue =$1 - \frac{3}{10} = \frac{7}{10}$