reynardo | Who said Maths couldn't be fun???

From the lesson we're presenting at school tomorrow to our small group of 9-10 year olds:

Jade the Mad Scientist wants to blow up the world. She needs to buy exactly 3 tonnes of Evil Scientist Explosive, but she's not allowed to buy it in one lot (because the governments of the world are aware of her Evil Plans). She also needs a detonator. The Countries sell in different amounts - what are the amounts she will need to buy to make her Evil Explosive?

4 countries sell the explosives, but in different amounts and with different limits.

Sodor sells bags of 1/4 tonne (max 6 bags)

Azania sells bags of 1/3 tonne (max 4 bags)

Duloc sells bags of 1/6 tonne (max 4 bags)

Guilder sells bags of 1/2 tonne (max 2 bags).

Each country also sells the detonators, but you can't buy a detonator from a country if you've bought explosives from them. The minions have to work out how much explosive to buy from each country, and from whom are they buying the detonator.

I'm not expecting the students to be able to say where these countries are, but I know you bunch of geeks will work them out too.