Question

At Mike’s favorite coffee shop, the coffee of the day is either a dark roast, a medium roast, or a light roast. From past experience, Mike knows that the probability of the coffee being a light roast is 0.15 and the probability of the coffee being a dark roast is 0.25. What is the probability of the coffee of the day not being a light roast or a dark roast on the next day that Mike visits the coffee shop?

a. 0.15
b. 0.25
c. 0.40
d. 0.60
e. 0.85

Answer 1

The correct option is d. 0.60

Explanation:

Consider the provided information.

At Mike’s favorite coffee shop, the coffee of the day is either a dark roast, a medium roast, or a light roast.

The coffee being a light roast is 0.15 and the probability of the coffee being a dark roast is 0.25.

Pr(Light roast) = 0.15

Pr(Dark roast) = 0.25

We need to find the probability of the coffee of the day not being a light roast or a dark roast on the next day that Mike visits the coffee shop.

`Pr(\text{Not being light or dark roast}) =1-Pr(\text{light roast})-Pr(\text{dark roast})`

`Pr(\text{Not being light or dark roast}) =1-0.15-0.25`

`Pr(\text{Not being light or dark roast}) =1-0.40`

`Pr(\text{Not being light or dark roast}) =0.60`

Hence, the correct option is d. 0.60