STRICTLY FOR STUDYING PURPOSES

My professor gave us this study sheet as well as the answer key, however he did not teach us how to solve them.

I don't just need the answers, I need a guide on how to obtain the answer.

Thank you!

The exchange rates between the dollar and pound are: 1.56$/f0.62f/$ 4) If you had $50,000, how many pounds would you get? 5) If you wanted to get 10,000, how many dollars would you need? 6) If you have 10,000, how many dollars would you get? 7) You turn $10,000 into pounds and then suddenly decide you don't want to travel to England after all. You exchange your pounds into dollars. How many dollars will you have