Question

Of the 102 customers at a restaurant 35 ate french fries and 55 ate hamburgers. Of these customers, 14 ate both. Find the probability that a customer chosen at random ate french fries given that they ate a hamburger

Answer 1

`20.3\%`

Explanation:

• There are 55+14=69 customers that ate hamburguers: the ones that only ate hamburguers (55) and the ones who ate both hamburguers and fries.
• Given that the customers ate hamburguers, the probability that they ate fries too is
  `(14)/(69) =20.29\%`.
• This is because once you know that the customers ate hamburguers, you are analisying a portion of the data: the one that fulfill the requirement of eating hamburguers. Then, looking inside of the group that ate hamburguers, 20.3% of the group ate both hamburguers and fries (14/69), and the rest (79.7%) only ate hamburguers.
• The probability of choosing randomly an individual who ate both things is then 20.3%.

Answer 2

Answer:35/102

Explanation: