Hamster wrote:

Paula can clan the room in 3 hours.  Paula and Maria can clean it in 2 hours.  How long would it take Maria working alone to clean the room.

Thanks.

What is the answer?

Let's look at how much they can do per hour (their "cleaning-up rate")

Paula is be able to clean 1/3rd of the room per hour. (1/3rd of a room times 3 hours = 1 room)

Paula and Maria together can clean 1/2 a room per hour.

So Maria's contribution is to speed things up from 1/3rd per hour to 1/2 per hour.

Let's calculate how much of an increase that is: 1/2 - 1/3 = 3/6 - 2/6 = (3-2)/6 = 1/6

So Maria is only really cleaning 1/6th of the room per hour.

So on her own it would be 6 hours.

(Maria is either very thorough at cleaning, or her heart isn't in it.)

Paula can clan the room in 3 hours.  Paula and Maria can clean it in 2 hours.  How long would it take Maria working alone to clean the room.

Thanks.