## Monday, 12 August 2013

### Maths and logic puzzle

My kids are doing Activities this week.

They have to take a packed lunch and a change of clothes (for the journey home, don't ask) with them every day = one rucksack each.

The lockers are only big enough for one rucksack and cost 20p a pop. They told me they need four 20p coins each day, because they take a locker each in the morning (costing two 20p coins), open the lockers at lunchtime, remove their packed lunches and put the rucksacks back in for the afternoon session (costong another two 20p coins).

By force of habit, I applied a few minutes thought to this and told them that they would actually only need three 20p coins each day if they used one locker for each rucksack with their changes of clothes and then put both their packed lunches into a third locker.

At lunchtime, they could open the third locker, remove their packed lunches, chuck away the wrappers and the plastic bag in which they carried them and hey presto. 20p saved. It's not the money, it's the principle, I told them. You've always got to try and beat the system.

They wouldn't accept this logic at all. Her Indoors took their side and gave them four 20p coins as per usual.

Ah well.

Bayard said...

You have my sympathy. Don't give up. Did they come up with the argument that taking a third locker was unfair?

View from the Solent said...

Incentives matter! If you had pointed out that (assuming 5 days activities) your method would save £1 each and then offered them half of it .....
Logic is tricky for youngsters.

B, yes, they did say it seemed a bit greedy taking a third locker. Fair play.

VFTS, no it would save £1 between them, i,e, 50p each.

Dinero said...

mayby after lunch the two bags fit into one locker

Bayard said...

How do you know they didn't take Her Indoors's money, use your system and pocket the savings?

Din, no they don't, I asked.

B, I would like to think so, but they have the annoying habit of snitching on each other, so they wouldn't be able to make it stick.

Ben Jamin' said...

Sorry, but saving 20p ain't cool when your at school.

Not in suburban leafy London anyhows;)

Ian B said...

I'm sorry, but I can't help asking about the whyfor of the change of clothes.