Answer:
The probability that a randomly selected customer orders a pizza or a salad is 80%
Step-by-step explanation:
Let's call
[tex]P_p[/tex] = the proability of someone asking for a pizza
[tex]P_s[/tex] = the probability that a customer orders a salad
Pp∩s = the probability that a customer orders a pizza and a salad.
We know from the statement of the problem that:
[tex]P_p[/tex] = 70% = 0.7
[tex]P_s[/tex] = 25% = 0.25
Pp∩s = 15% = 0.15
We want to know the probability that a randomly selected customer will order a pizza or a salad. Then, by set theory, that probability is calculated as:
Pp∪s = [tex]P_p[/tex] ∪ [tex]P_s[/tex] - Pp∩s
So:
Pp∪s = Pp + Ps - Pp∩s
Where Pp∪e is the probability that the customer orders a pizza or a salad, but not both at the same time.
Pp∪e = 0.7 + 0.25 -0.15
Pp∪e = 0.8
Finally, the probability that a randomly selected customer orders a pizza or a salad is 80%