Taxing your mind

I have come across a problem to which I have so far been able to find no satisfactory answer. I wonder if any of your readers can help me!

A man witnesses a crime involving a taxi. He says that the taxi is blue. You know from previous research that witnesses are correct 80% of the time when making such statements. You also know that 85% of the taxis in the town are blue.

Using these two pieces of information, work out the probability that the man has indeed seen a blue taxi.

Geoff Tennant, Muswell Hill, London

This problem is discussed in a separate article in this issue. See "the taxi problem" - PM.

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Helping hand

Hello. I'm a high school student from northern California and I just wanted to let you know that your information on Daniel Bernoulli along with the graphics have been a helpful source for my end of the year mathematician project in Calculus. Thanks for keeping up the page, it is pretty cool.

Dane Thompson

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Trentham High School

Hi, it's the pupils from T.H.S. here. We are having a really great time here on your web address. We are completing our exams soon and believe it will be a great help in our studies.

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Miscellaneous comments

More Puzzles and practical work needed although generally quite good.

Craig Wagstaff

Point taken. We have put a practical assignment on testing the Bernoulli equation in this issue. See "Testing Bernoulli: a simple experiment"- PM.

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Thanks a lot!

Anon

We thought that this information was most helpful.

Alax Mack and Kim Bennett

Hello world. I am Chell and this here is my friend Jake. How are you today? I hate maths, don't you?

Chell and Jake

Thanks to all who sent similar good wishes - PM.

How to contact us: Any comments?