What is the most powerful currency in the world?

Answer 1

1 British pound = 1.5668 U.S. dollars

1 Kuwaiti dinar = 3.56125 U.S. dollars

British pound is not the most powerful currency in the world.

Kuwaiti Dinar is the most powerful currency in the world.

http://en.wikipedia.org/wiki/Kuwaiti_dinar

In the second line of this article you will find your answer.

the whole world knows the American dollar is by far and always has been by far the most widely accepted and most powerful currancy on earth.

The above sentence is contentious and untrue. The US dollar is used in much international trade, but other currencies are used as well, and most international trade is in the currencies of the two trading countries.

To call it the "most powerful" depends on what you mean by powerful.

Finally "always has been" is impossible, in the 19th century most internationa trade was conducted in the British pound. And before 1776 the US dollar did not even exist.