Rate/Distance problems

[xfactor]

<p>Hey guys, I was wondering how to exactly solve problems that deal with rate/distance. like the questions that ask If kid a can do it in x/per hr and kid B can do it in y/per hr. How long with it take them to do z amount?...
I want to find the quickest way to do these problems, since they give me the most trouble.</p>

<p>thanks in advance!</p>

[Soulside_Journey]

<p>Simply add their speeds.</p>

<p>For example, if Kid A can open 80 boxes per hour and Kid B can open 50 boxes per hour, how long will it take them to open 300 boxes?</p>

<p>80 and 50 sum to 130 boxes per hour. Then divide 300 boxes by 130 to get approximately 2.3 hours.</p>