Question

Paul's bathtub is clogged. He has to empty 30 liters of water by hand. Paul has a 3- liter, a 4- liter, and a 5 liter bucket. Of Paul carries 2 buckets each trip, what combinations of sizes allow him to empty the bathtub in exactly four trips?

Answer 1

3 and 4 + 3 and 4 + 3 and 4 + 4 and 5 = 30