Answer:
36 mi
Explanation:
Remember that distance = rate times time.
Thus, while biking at 12 mph for 1 hr, Kristen covers
(12 mph)(1 hr), or 12 miles;
While riding the train at 24 mph for 1 hr, she covers 24 mi.
Adding these two results together: The total distance from home to work is 12 mi + 24 mi = 36 mi