Answer:
D. 4
Step-by-step explanation:
The faster you go, the faster you get home (theoretically anyway) and vice versa. So if your speed is doubled, it'll take half the time to get home. But if your speed gets halved, it'll also take double the time to get home.
So, if at 60 mph it takes 1 hour to get home, then if your speed is divided by four to 15 mph, you need to multiply the time by the same number and thus the answer is 4.
If the question is 40 - 
, then you would do 16 ÷ 4 = 4, and then 40 - 4 = 36.
If the question is 
, then you divide both 40 and 16 by 4, to get 10 - 4 = 6.
I hope this helps!
