It is pretty simple to figure this out, all you have to is find out how many words carl can type in 1 minute and you do that by dividing 180/2 and that would give you 90. So now that you know carl types 90 wpm, you just multiply 90 by 5 and that will give you 450.
So now you know that carl can type 450 words in 5 minutes, which is quite impressive.