Question

Ellie has a new restaurant, and she tracked the menu items ordered in one day. The probability that the soup of the day was ordered was 0.6 . The probability that a side salad was ordered was 0.4 . The probability the soup of the day and a side salad were ordered was 0.3 . Use the addition rule to determine the probability that a randomly selected order included the soup of the day or a side salad.

Answer 1

0.7

Explanation:

Probability addition rule:

`P(A\cup B)=P(A)+P(B)-P(A\cap B)`

In your case,

Event A = the soup of the day was ordered

Event B = the side salad was ordered

Event
`A\cap B` = the soup of the day and the side salad were ordered

Event
`A\cup B` = the soup of the day or the side salad were ordered

Hence,

`P(A)=0.6\\ \\P(B)=0.4\\ \\P(A\cap B)=0.3`

and

`P(A\cup B)=0.6+0.4-0.3=0.7`