An electronics company makes communications devices for military contracts. The company just completed two contracts. The Navy contract was for 2,700 devices and took 25 workers two weeks (40 hours per week) to complete. The Army contract was for 7,500 devices that were produced by 40 workers in three weeks. What is the labor productivity for each contract? On which contract were the workers more productive? What is the percentage difference of productivity between the two contracts?