4) Able can harvest a lime crop in 4 days. Barney can do it in 5 days. Charlie would take 6 days. How long will it take them to complete the harvest if they work together?

5) Pam's favorite recipe for fruit punch requires 15% apple juice. How much pure apple juice does she need to add to 2 gallons of punch that already contains 8% apple juice to meet her standards?

6) Jane has 40 liters of 60% acid solution. How many liters of water must be added to form a solution that is 40% acid?