Working alone, it takes Randy 11 hours to inventory the instrument shop. Liz can complete the same inventory in 10 hours. If they worked together, how long would it take them to complete the inventory of the instrument shop?

Three brothers X, Y, and Z work at different speeds. When the slowest two work together they take n days to finish a job. When the quickest two work together they take m days to finish the same job. One of them if works alone, would take thrice as much time as it would take when all three of them work together. How much time is required to finish the same job if all three work together?

Working at their respective constant rates, Paul, Abdul and Adam alone can finish a certain work in 3, 4, and 5 hours respectively. If all three work together to finish the work, what fraction of the work will be done by Adam?

Machine A can produce of a ton of paintbrushes in one hour. Machine B can produce of a ton of paintbrushes in one hour. Working together at their individual rates, how long would it take the two machines to produce 2 tons of paintbrushes?

Pam and Stanley packed several boxes with reams of paper. While both packed, Pam packed 60% of the boxes. After Pam stopped, Stanley packed the same number of boxes that he had packed while working with Pam. What is the ratio of the number of boxes Pam packed to the number of boxes Stanley packed?

A group of 8 machines that work at the same constant rate can complete 14 jobs in 7 hours. How many hours would it take 17 of these machines to complete 34 of these jobs?

David and Michael charged Mr. Jimenez $3,000 to remodel his basement. To complete the project, David worked 4 days alone, Michael worked 1 day alone, and they worked 10 days together. If they each received the same amount of money for each day that they worked, how much of the $3,000 did David receive?

John would have reduced the time it took him to drive from his home to a certain store by 1/3 if he had increased his average speed by 15 miles per hour. What was John's actual average speed, in miles per hour, when he drove from his home to the store?

Two pools in the shape of rectangular prisms are being filled with water by pumps. The first pump fills its pool completely in one hour. The second pumps water twice as fast as the first pump, and fills a pool that is twice the width, twice the length, and the same depth of the first pool. How many hours does it take the second pump to fill its pool?

Two machines, working simultaneously at their respective constant rates, can print 400 sheets in 5 hours. If one machine can print 200 sheets in 3 hours, what is the rate of the other machine, in sheets per hour?