KöMaL 2013 K397

A certain island that is also a country has its own currency, the wooden knut. Everyone pays tax to the state (independently of the size of his or her income). The tax is a certain percentage of the income. However, the government supports the raising of children, therefore every family receives a tax reduction of a certain number of wooden knuts per child (for example, the reduction is twice as many wooden knuts for two children as for a single child). One particular family has an annual income of 1500000 wooden knuts and one child. They pay a tax of 150000 wooden knuts. Another family has an annual income of 2500000 wooden knuts, two children and a tax of 225000 wooden knuts to pay. What percentage of the income is the tax on the island, and what is the tax allowance per child?