Sorry to disturb the vast majority of this math community. I ran into a problem I do not under stand how to solve.

I know this is probably the easiest question but for some reason I cannot see through the words to find my equation.One power plant releases a certain amount of toxic waste into the atmosphere twice as fast as another plant. Together they release that amount in 3 hours. How long does it take the slower plant to release that amount?

I attempted x+0.5x=(3)(2x)

but that is simply wrong.

Can someone please give me the correct equation?

I really appreciate it, thanks.