While working alone at their constant rates computer X can process 240 files in 4 hours, and comp Y 240 files in 8 hrs. If all files processed by these comp. are the same size how long would it take the two comp. working at the same time at their respective constant rates , to process a total of 240 files?

There is a total of 1,800 pages that needs to be typed. If it takes 90 minutes when a types alone, 45 minutes when b types alone, and 30 minutes when c types alone. How many minutes does it take if 3 of them work together?

Working together, Jeff and Ashley painted their apartment in 6 hours. If Jeff had been working alone, he could have painted the whole apartment in 10 hours. How many hours would it have taken Ashley to paint the apartment alone?

Eric can vacuum the carpenting in a particular office suite in 20 minutes. Ray can vacuum the the carpenting in the same office suite in 30 minutes. If they work together at their individual constant rates, how many minutes will they take to vacuum the carpenting in the office suite?

Sharon and Ramla frequently mow their grandfather's yard. Working at her normal pace, Sharon can mow the yard in 5 hours. When Sharon and Ramla work together, each at her own normal pace, they can mow the yard in 3 hours. Yesterday, Ramla mowed the yard by herself. Given that Ramla was mowing at her normal pace, how long, in hours, did it take for Ramla to mow the yard?

N men can do a piece of work in 6 days. The same work can be done by (N + 3) men in 4 days. Find the value of N.

A helium pump releases 1,184 units of helium every 37 seconds. At this rate, how many units of helium will it release in a minute?

Each of 10 machines works at the same constant rate doing a certain job. The amount of time needed by the 10 machines, working together, to complete the job is 16 hours. How many hours would be needed if only 8 machines, working together, were used to complete the job?

A small water pump would take 2 hours to fill an empty tank. A larger pump would take hour to fill the same tank. How many hours would it take both pumps, working at their respective constant rates, to fill the empty tank if they began pumping at the same time?

Ed's own pump, operating alone at its constant rate, can empty his swimming pool in 15 hours. The pump Ed rented, operating alone at its constant rate, can empty his swimming pool in 5 hours. How many hours will it take the two pumps, operating simultaneously and independently at their respective constant rates, to empty Ed's pool?