**Problem of the Week**

Problem B

Honesty - the Best Policy?

A reporter is doing interviews at a convention attended by 500 people.

40% of these people always tell the truth.

20 of them will always lie.

The remaining people each sometimes tell the truth and sometimes lie.

Suppose that she interviews a person at random.

As a fraction, what is the probability that the person always lies?

As a fraction, what is the probability that the person always tells the truth?

Suppose she interviews Joe Public, a person at the convention. The last time she interviewed him, he only told her the truth, so she knows he must be a person who always tells the truth or a person who sometimes tells the truth and sometimes lies. What is the probability that Joe Public always tells the truth?

**Strand:** Data Management and Probability