Two boats are heading towards each other at constant speeds of 5 miles/hr and 23 miles/hr respectively. They begin at a distance 20 miles from each other. How far are they (in miles) one minute before they collide ?
Choices
A) 1/12
B) 7/12
C) 1/6
D) 1/3
E) 1/5
The question asks: how far apart will they be 1 minute=1/60 hours before they collide?   Since the combined rate of the boats is 5+23=25 mph then 1/60 hours before they collide they'll be rate*time=distance --&gt; 28*1/60=7/15 miles apart.   Answer: 7/12.
<result>B</result>
Two boats are heading towards each other at constant speeds of 5 miles/hr and 23 miles/hr respectively. They begin at a distance 20 miles from each other. How far are they (in miles) one minute before they collide ?