Tuesday, 22 March 2011

Eagle Eyed Pedant Of The Week

From The Daily Mail:

A Government television advert to recruit teachers was ridiculed today after a 15-year-old boy spotted that a maths question has the wrong answer.

Chris Coombs, 15, noticed the mistake in the 30-second advert, which is regularly shown on Channel 4 and ITV. The Government-funded clip shows a teacher writing '(g2)7 = g?' on a whiteboard and later 'solving' it with the answer 'g2 x g7'. But the correct answer for the algebraic equation is g14...


NB, g2 x g7 = g9, not g14.

4 comments:

Decnine said...

It's a long time since I did A level maths and maybe my memory is faulty. However, although your NB is right (g^2 x g^7 = g^9) that isn't the question as set.

As set, the question is equivalent to g^7 x g^7 = g^14.

Mark Wadsworth said...

Dec, agreed. My NB was for the benefit of people who thought that the answer to "the question as set" might be G^9, or that G^7 x G^2 = G^14.

TheFatBigot said...

This sort of stuff takes me back to when I had hair.

I don't know how to get little numbers at the top right of letters so please treat all numerals attached to Gs in the following as being tiny and high. G2 x G7 involves two independent numbers being multiplied, the first is G2 and the second is G7, whereas (G2)7 is a different sum. It is G squared multiplied by itself seven times. If G is 2, the first answer gives a total of 128 and the correct answer is 16,348. It is no coincidence that 128 squared is 16,348.

It's rather like a government procurement contract. The price is said to be £128million which is actually the square root of the final cost.

Mark Wadsworth said...

2^9 = 512, not 128.
2^14 = 16,348