Suppose that 50 identical batteries are being tested. After 8 hours of continuous use, assume that a given battery is still operating with a probability of 0.70 and has failed with a probability of 0.30.

What is the probability that fewer than 40 batteries will last at least 8 hours?

A. 0.7986

B. 0.9211

C. 0.9598

D. 0.0789

In a history class, students take a weekly multiple choice quiz consisting of 6 questions, each with 4 possible answers. If a student randomly guesses at the answer to each question for every quiz, then what is the mean number of correct answers the student will get on each quiz?

Round your answer to one decimal place as necessary. For example, 4.5 would be a legitimate entry.

Answer:

An ice cream vendor sells three flavors: chocolate, strawberry, and vanilla. Forty five percent of the sales are chocolate, while 30% are strawberry, with the rest vanilla flavored. Sales are by the cone or the cup. The percentages of cones sales for chocolate, strawberry, and vanilla, are 75%, 60%, and 40%, respectively. For a randomly selected sale, define the following events:

= chocolate chosen

= strawberry chosen

= vanilla chosen

= ice cream on a cone

ice cream in a cup

Find the probability that the ice cream was strawberry flavor, given that it was sold in a cup. Place your answer, rounded to 4 decimal places, in the blank. For exampe, 0.3456 would be a legitimate entry.