Final answer:
Two steamers traveling in opposite directions at 20 mph will each cover a relative speed of 40 mph when moving apart. Therefore, it will take them 1.5 hours to be 60 miles apart, which is the correct answer, option B.
Step-by-step explanation:
The question is asking to determine the time it takes for two steamers, each traveling at 20 miles per hour in opposite directions, to be 60 miles apart. Since they are moving away from each other, their relative speed is the sum of their speeds. The relative speed is thus 40 miles per hour (20 mph + 20 mph).
To find out how long it takes for them to be 60 miles apart, we can use the formula time = distance/speed. Plugging the values into this formula, we get time = 60 miles / 40 miles per hour = 1.5 hours.
Therefore, the correct answer is B. 1.5 hours. It will take 1.5 hours for the two steamers to be 60 miles apart.