Question

paul bathtub is clogged he has to empty 30 liters of water by hand he has a 3 liter four liter and a five liter bucket if he carries two buckets each trip what combination of sizes allowed with him to empty the bathtub in exactly four trips

Answer 1

5 and 3 = 8 liters , 5 and 4 = 9 liters, and 3 and 4 = 7 liters.

8 + 7 + 8 + 7 = 30 liters, so he can take the 5 liter bucket with the 3 liter bucket twice, and then use the 3 liter bucket and the 4 liter bucket twice.