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There are two unmarked buckets by a stream. The buckets hold 19 and 8 gallons of​ water, respectively. How can 14 gallons of water be​ obtained, to take​ home? Complete the sequence below. The numbers represent the number of gallons in each bucket in each successive step.

User Waltari
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1 Answer

4 votes

9514 1404 393

Answer:

Fill the 19-gal bucket. Use that to fill the 8-gal bucket twice, so that 3 gal remains in the 19-gal bucket. Move that to the 8-gal bucket. Fill the 19-gal bucket again and use that to top off the 8-gal bucket. The 19-gal bucket now contains 14 gallons.

Explanation:

The problem is equivalent to solving ...

19a +8b = 14

One solution is (a, b) = (2, -3). That means you can obtain the required amount by filling the 19-gallon bucket 2 times, and using that source to fill (and empty) the 8-gallon bucket 3 times.

The third attempt to fill the 8-gallon bucket from the 19-gallon bucket will result in only 3 gallons in the 8-gallon bucket. The last 5 gallons needed to finish filling the 8-gallon bucket the third time come from the second filling of the 19-gallon bucket. After that transfer of 5 gallons, the 19-gallon bucket contains the required 14 gallons.

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We don't know what your steps are supposed to look like, but we can write them as ...

(19-gallon bucket, 8 gallon bucket)

(0, 0) . . . start

(19, 0) . . . first fill

(11, 8) . . . first transfer

(11, 0) . . . first dump

(3, 8) . . . second transfer

(3, 0) . . . second dump

(0, 3) . . . third transfer

(19, 3) . . . second fill

(14, 8) . . . 4th transfer -- one bucket has 14 gallons in it

Optional:

(14, 0) . . . third dump -- one bucket has 14 gallons in it

User Jason Nam
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