## Currencies

Money is exchanged from one currency into another in a certain ratio, called the exchange rate. The exchange rate of US dollars to British pounds is $1.6:£1. A British pound buys more than 1 US dollar – I suppose that means English people are better than Americans.

To change any amount of dollars into pounds or vice versa, construct a table. To change $60 into pounds, construct the table below.

$ | £ |

1.6 | 1 |

60 | x |

The columns or rows are in a certain ratio, soorhenceso $60 buys £37.50.

To change £120 into dollars construct the table below.

$ | £ |

1.6 | 1 |

x | 120 |

The columns or rows are in a certain ratio, soorhenceso £120 buys $192.

Suppose there are three currencies – pounds £, dollars $ and Roubles R. £1 buys $1.6 or R56. I guess that means British people are better than Americans but much better than Russians.

I want to change $140 into Roubles.

The £:$:R ratio is 1:1.6:56. The above table becomes

$ | R |

1.6 | 56 |

140 | x |

The columns or rows are in a certain ratio, soorhenceso $140 buys R4900.