hey i have 2 problems that i need help with... work rate word problems...

Dan can carpet his house in 9 hours. Mike can carpet the same house in 13 hours. How long would it take them to lay the carpet if they worked together?

Jones Conctruction company crew needs 28 hours to do a job. Smith contruction company needs 34 hours to do the same job. If both crews work for 9 hours, how long will it take the Smith conctrucion company to finish the job alone?

thanks!! postscript: th last one doesnt make sense to me ... but thats the way my teacher wrote it!!

GAR