John can type 2/3 of a manuscript in 12 hours. If he is joined by Laura, they can complete the typing in 2 hours. How many hours would Laura take to type the manuscript working alone?
A. 4.5 hours
B. 2 hours
C. 2.25 hours
John will take 18 hours to type the thing by himself. Laura does 8/9 of the work and John does 1/9. Laura can do it alone in 2 hours 15 minutes. which is 2 1/4 hours. So the answer would be C.) 2.25 hours.
