Why do currency differ in value - can it not just be 1 is to 1. e.g R1 1. what is the matter.. what is the influence or the real reason here?

The reason is that currencies in different countries developed independently of one another. Sure, they can be made equal, but that would basically mean several countries having a single currency. The best example that this is possible is the Euro. You might think of this as a prototype for a future world currency.