Word problem: find time to complete job, if each works alone

[dayton1]

Here is a problem I cannot figure out....any help?

The Hp office jet g85 works twice as fast as the laser jet II. When the machines work together, a university can produce all its staff manuals in 15 hours. Find the time it would take each machine, working alone, to complete the same job.

I can't figure out the formula to use!!

 

[galactus]

Think about how much each can do in one hour.

\(\displaystyle \L\\\frac{1}{2x}+\frac{1}{x}=\frac{1}{15}\)

 

[dayton1]

Ahhhh! thanks a bunch....I have such trouble with word problems...I just cannot conceptualize them! Thanks again! :lol: