Simple Maths Problem?

[barry1010]

Courtesy of Martin Lewis.  What's your answer?

 How much would you have made if you...
- Bought a car for £6,000
- Sold it for £7,000
- Re-bought it for £9,000
- Sold it again for £11,000

PS this is a simple question of the numbers, ignore inflation, tax, erosion of money etc

[JJ109]

3000 pounds

[Old_Geezer]

Agreed

[newmodarmy]

£3000

[ToraToraTora]

3 bags, 1 on the first deal 2 on the second.

[barry1010]

If all the money I have at the start is £6k I am £1k up on the first sale and now have £7k.

I buy it for £9k so am now -£2k.

[barry1010]

Pressed enter too soon.

So now I am £2k down and sell the car for a £2k more than I paid.

How is that a profit?  Where have I gone wrong?

[ToraToraTora]

no no no!

On the first deal you make 1000. Put that to one side put it in a shoe box forget it, it does not exist.

Now on the second deal you make 2000, you still have the 1000 in the shoe box. So now you have made 3000 total, tada!

[ToraToraTora]

the two deals are not linked arithmetically.

imagine the second deal was another car.

[barry1010]

Thank you, TTT

[JJ109]

Agree TTTs way, as that is the way I did it also

....but after you buy it for 9000 you are not 2000 down, you have spent 2000 more than your original 6000, ie you have spent 8000 sell for 11000 = 3000 profit

[Cloverjo]

The way I looked at it was: the two amounts I paid add up to £15,000. The two amounts I received add up £18,000. £18,000 - £15,000 = £3,000

[ToraToraTora]

Another way: You've laid out 15k and got 18k back in, 3k up tada!

[ToraToraTora]

jo snap!

[THECORBYLOON]

If you look at what was spent on buying the car,£6,000 and £9,000, that is £15,000 in total.

Looking at the money from selling the car, £7,000 and £11,000, that is £18,000 in total.

That means £15,000 out and £18,000 in or £3,000 in profit.

[barry1010]

Thanks all

[barry1010]

Did nobody else see it the way I did?

[ToraToraTora]

That's the thing with maths, half the battle is isolating the approach. I can see why you could think the way you did primarily because it's the same car, so that can throw you. The trick is to see that it's two separate transactions and to treat it as such even though it's the same car.

[ToraToraTora]

Here's a classic....

https://www.theanswerbank.co.uk/ChatterBank/Question1874388.html

 

[Old_Geezer]

What you have isn't relevant. It's how much up or down you are stage by stage. There are various ways to work it out, maybe the simplest is:

 

6k+9k=15k spent,

7k+11k=18k gained,

18k-15k=3k profit.