Since the number of miles and number of km is over one hour, the only thing you need to worry about it the number of miles in a kilometer (the numerator).
1 mile is approximately 1.60934 kilometers, so to find how many kilometers are in 50 miles, you would multiply 1.60934 by 50.
1.60934 * 50 = 80.467
Since 50 miles is rounded to the nearest whole number, I expect that the kilometers should be given in the nearest whole number, so the final answer is 80 kilometers.
