The answer is $2 = 1 British pound.
To calculate the rate of exchange, we will use a proportion method. If 10,000 British pounds is $20,000, then 1 British pound is x dollars:
10,000 British pounds : $20,000 = 1 British pound : x
The cross products are equal:
x * 10,000 British pounds = $20,000 * 1 British pound
x = $20,000 * 1 British pound : 10,000 British pounds
x = $2.
So, the exchange rate is $2 = 1 British pound.
