Question 1197148
<br>
Similar to the familiar formula for time,<br>
(time) = (distance)/(rate)<br>
there is the formula<br>
(time) = (difference in distances)/(difference in rates)<br>
In this problem, the distance to be made up by the second ship is 20 miles; the rate at which that distance is made up is 50-40 = 10mph.  So the time required for the second ship to make of the distance is 20/10 = 2 hours.<br>
ANSWER: 2 hours<br>
Side note....  40mph and 50mph are not reasonable speeds for large ships.<br>