Question

A survey is taken among customers of a fast-food restaurant to determine their preference for hamburger or chicken. Of 400 respondents selected, 290 were children and the rest were adults. 260 preferred hamburger and the rest preferred chicken. 175 of the children preferred hamburger.

The probability that a randomly selected individual is an adult is ________.

(Round your answer to three decimal places. Express your answers as a probability, not a percentage.)

Answer 1

Solution:

Given:

Of 400 respondents selected, 290 were children and the rest were adults.

Thus number of adults = 400 - 290 = 110

260 preferred hamburger and the rest preferred chicken.

Thus number of preferred chicken = 400 - 260 = 140

175 of the children preferred hamburger.

	hamburger	Chicken	Total
Children	175	(290-175)= 115	290
Adult	(260-175) = 85	(110-85) = 25	110
Total	260	140	N = 400

We have to find: the probability that a randomly selected individual is an adult is____?

P( individual is an adult ) = Total Adults / N

P( individual is an adult ) = 110 / 400

P( individual is an adult ) = 0.275