Two boats are heading towards each other at constant speeds of 5 miles/hr and 21 miles/hr respectively. They begin at a distance 20 miles from each other. How far are they (in miles) one minute before they collide ? Select the correct option: A) 1/12 B) 5/12 C) 1/6 D) 13/30 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+21= 
<gadget id="calculator"> 5+21</gadget>
<output>26</output>
26 mph then 1/60 hours before they collide they'll be rate*time=distance --&gt; 26*1/60=13/30 miles apart.   Answer: 13/30.
<result>D</result>
Two boats are heading towards each other at constant speeds of 5 miles/hr and 21 miles/hr respectively. They begin at a distance 20 miles from each other. How far are they (in miles) one minute before they collide ?