Hi All,

I probably encountered a major brain fart, but as I was going through the ETS math review guide, I had a really hard time understanding a word problem example in the algebra-application session.

Example 2.7.4: Working alone at its constant rate, machine *A* takes 3 hours to produce a batch of identical computer parts. Working alone at its constant rate, machine *B* takes 2 hours to produce an identical batch of parts. How long will it take the two machines, working simultaneously at their respective constant rates, to produce an identical batch of parts?

First, I set x=time in hrs for both machine working simultaneously to produce an identical batch of parts

Machine A hourly production rate=1/3 batch

Machine B hourly production rate=1/2 batch

The book gives the equation of 1/3+1/2=1/x

I just had a hard time understanding the 1/x part, isn’t it suppose to be 1/3+1/2=x?

Appreciate response and explanations!