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May 1997

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.


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


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.


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.


Thanks a lot!


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.

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