Answer: 4 miles per hour.
Explanation:
We can calculate her feet per second: 75 ft/12 sec is 6.25 ft/sec
Then convert to miles per hour. 1 mph = 1.46667 ft/sec
Divide 6.25/1.46667 = 4.261353951 mph
Round that to 4 ¹/₄ mph or, as per the directions in this question, "to the nearest mile per hour.
4 mph.
It is also possible to get a similar answer by changing the feet to a fraction of a mile, (about 0.142mi) and the time to a fraction of an hour (about 0.00333) and dividing those numbers, but that may be doing too much!
