### Home > MC2 > Chapter 9 > Lesson 9.3.3 > Problem9-111

9-111.

A box contains $15$ yellow, $15$ orange, and $15$ green tennis balls. If Izzy draws a tennis ball at random out of the box, what is the probability that he drew either a green or an orange tennis ball? Show your work and express your answer as a percent.

$\text{Probability }= \frac{\text{number of tennis balls we're looking for}}{\text{Total number of tennis balls}}$

How many green and orange tennis balls are there?
How many total tennis balls are there?

$15$ green $+ 15$ orange $= 30$ green or orange tennis balls.
$15$ green $+ 15$ orange $+ 15$ yellow = 45 total tennis balls.

$\frac{30}{45} \text{ Now convert this fraction to a percent.}$

$66 \frac{2}{3}$