On a trip you had to change your money from dollars to brittish pounds . you got 560 pounds for 800 dollars. which is a unit rate that describes the exchange?

FROM dollars TO pounds means that you have to do this to find how many dollars per pounds. You have to put the first currency (dollars) over the second (pounds)

Now, you just divide, which makes the denominator (pounds) into one so you find how many dollars are in 1 pound.
You end up with 1.42857...............
You can round this to around 1.43 dollars per 1 British Pound