A Quick Maths Test

  Confab 18:09 10 Mar 07
Locked

If you KNOW the answer then don’t post it yet. It might spoil it for others.

A bottle of wine cost £10.00. The wine costs £9.00 more than the bottle. How much does the bottle cost?

Confab

  Kate B 18:16 10 Mar 07

*head hurts*

*rubbish at maths*

  Confab 18:17 10 Mar 07

OK

The answer is 50p

Confab

  rodriguez 18:18 10 Mar 07

Most people would say £1, but there must be some sort of clever twist that means there is another method to work it out which means the answer isn't £1 and I'll now probably spend all night trying to work out the right answer... :-P

  Confab 18:19 10 Mar 07

You won’t have to spend any time working it out now!

  Kate B 18:22 10 Mar 07

*head hurts even more*

Please explain!

  rodriguez 18:24 10 Mar 07

Ahhh I worked out how you do it now - I won't post yet though, as other people will probably want to work it out. Didn't take as long as I thought. Quite a good one that. ;-)

  Kate B 18:25 10 Mar 07

Ah! GOT IT!!!

  Blackhat 18:39 10 Mar 07

Confab, here's another math test with full explanation.

We start with two quantities a & b which are equal.

Equation 1. a=b

We can multiply both sides of an equation by the same value without affecting the equality. Lets multiply both sides by a.

Equation 2. a²=axb

We can subtract the same value from both sides of an equation by the same value without affecting the equality. So lets subtract b² from both sides.

Equation 3. a²-b²=axb-b²

a²-b² can also be represented by (a+b)x(a-b).

axb-b² Is also the product of bx(a-b). so we now have,

Equation 4. (a+b)x(a-b)= bx(a-b)

We can divide both sides of an equation by the same value without affecting the equality. Lets divide by (a-b). This means the (a-b) factor drops from both sides. We are left with,

Equation 5. a+b=b

Since a=b we can say that a+b is the same as b+b therefore;

Equation 6. b+b=b

  Confab 18:43 10 Mar 07

oh!

  Mr Mistoffelees 18:52 10 Mar 07

Equation 7. a=0

Equation 8. b=0

Otherwise equation 6. makes no sense!

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