Here's the calculation:
50.00 GBP X 1.28 USD/GBP = 64.00 USD
Therefore, 50.00 UK pounds is equivalent to approximately 64.00 US dollars at the given exchange rate. Please note that exchange rates can fluctuate over time, so the actual conversion amount may be slightly different depending on when you make the conversion. It's always a good idea to check the latest exchange rates before making any currency conversions.