Answer: 12 hours
Explanation:
Let's set the speed as "s".
Remember that distance = speed * time
So, plugging the numbers given...
7 = s * 8.4
Divide both sides by 8.4
s = 5/6
Now, plug this into the distance = speed * time, with the distance being 10. Set the time as "t"
10 = 5/6 * t
Divide both sides by 5/6
12 = t
So, it would take 12 hours for the snail to crawl 10 miles.