8. In rural third world countries, farmers use a conical bucket, the "Gầu Dây” to drain/transfer
water from one rice field to another. If the height
is 20" & the diameter of the opening is 15”, how
much cubic feet of water can two farmers drain
in three hours if their rate is 28 “gầu" per
minute?

9514 1404 393

  6872 cubic feet

Step-by-step explanation:

The volume of the conical bucket is ...

  V = 1/3πr²h

  V = 1/3π(15/2 in)²(20 in) = 375π in³

There are 60 minutes in 1 hour, so 3×60 = 180 minutes in 3 hours.

If each of 2 farmers can transfer 28 buckets per minute the total amount transferred is ...

  (375π in³)(180 min)(2 farmers)(28/min/farmer) = 3,780,000π in³

There are 1728 in³ in 1 ft³, so this is ...

  (3,780,000π/1728) ft³ = 2187.5π ft³, about 6872 cubic feet.

hm let me think hm think think hm think yes