Conditional Probability

This Venn diagram shows the results when 30 people were asked whether they have a cat or a dog.

Find the probability that a person selected at random has a cat given that they have a dog.

The two way table shows information about the gender and age of employees at a company.

A person from the company is chosen at random. Find the probability that the person is female given that they are 30 or over.

Lily has the following cards,

A A B B B C C D

Lily picks two cards. The first card is an A. Find the probability that the second card is also an A.

A football team contains 9 boys and 6 girls.

The coach is choosing players at random for a match.

The first player picked is a boy.

Find the probability that the second player picked is a girl.

Ben and Jacob randomly pick a packet of crisps from a multipack containing 6 packs of ready salted and 6 packs of cheese and onion. What is the probability they both pick a packet of ready salted crisps?

Give the answer in its simplest form.

Fred is a golf player. The probability that Fred gets a hole in one on a dry day is 0.2 and the probability that Fred gets a hole in one on a rainy day is 0.1. Fred is going to play golf tomorrow.

 

The probability that it will be raining is 0.7.

Find the probability that Fred will get a hole in one.

• 0.13

• 0.14

• 0.07

• 0.3

Vicky has a box of chocolates containing 5 white chocolates and 11 milk chocolates. Vicky eats one milk chocolate.

 

Find the probability that the next chocolate she picks is also a milk chocolate.

Mathematical Equivalence

ON

There are 8 counters in a bag. Three of the counters are red and the rest are blue. A counter is chosen at random. It is not replaced. A second counter is chosen at random.

 

Calculate the probability that both counters are blue.

Mathematical Equivalence

ON