[Guest]

you have flask A, which holds 13 ounces, and flask B, which

holds 21 ounces. Using only the operations of filling a flask, emptying a

flask, and pouring one flask into another (until either the first is

empty or the second is full), you must manage to put exactly 17 ounces of

water in flask B, leaving flask A empty.

[Guest]

1. Fill flask B, 21 ounce, then pour from B to A, 21-13=8 ounce left in B. Empty A, then pour the water from B to A. Now A has 8 ounce. We can still pour 13-8=5 into A.

2. Fill B, pour water from B to A. Now B has 21-5=16. Empty A, pour the water from B into A. Now B has 16-3=3 left. Empty A. Pour the 3 ounce from B to A. Now A has 3 ounce. Can still have 13-3=10.

3. Fill B, pour water from B to A. Now B has 21-10=11.Empty A, pour the water from B into A. Now A has 11 and can still accept 13-11=2.

4. Fill B, pour water from B to A. Now B has 21-2=19. Empty A, pour the water from B into A. Now B has 19-13=6 left. Empty A. Pour the 6 ounce from B to A. Now A has 6 ounce and can accept 13-6=7 more.

5. Fill B, pour water from B to A. Now B has 21-7=14.Empty A, pour the water from B into A. Now B has 14-13=1 left. Empty A. Pour the 1 ounce from B to A. Now A has 1 ounce and can accept 13-1=12 more.

6. Fill B, pour water from B to A. Now B has 21-12=9.Empty A, pour the water from B into A. Now A has 9 and can still accept 13-9=4.

7. Fill B, pour water from B to A. Now B has 21-4=17 ounce. We're done.

[dark_magician_92]

1. Fill flask B, 21 ounce, then pour from B to A, 21-13=8 ounce left in B. Empty A, then pour the water from B to A. Now A has 8 ounce. We can still pour 13-8=5 into A.

2. Fill B, pour water from B to A. Now B has 21-5=16. Empty A, pour the water from B into A. Now B has 16-3=3 left. Empty A. Pour the 3 ounce from B to A. Now A has 3 ounce. Can still have 13-3=10.

3. Fill B, pour water from B to A. Now B has 21-10=11.Empty A, pour the water from B into A. Now A has 11 and can still accept 13-11=2.

4. Fill B, pour water from B to A. Now B has 21-2=19. Empty A, pour the water from B into A. Now B has 19-13=6 left. Empty A. Pour the 6 ounce from B to A. Now A has 6 ounce and can accept 13-6=7 more.

5. Fill B, pour water from B to A. Now B has 21-7=14.Empty A, pour the water from B into A. Now B has 14-13=1 left. Empty A. Pour the 1 ounce from B to A. Now A has 1 ounce and can accept 13-1=12 more.

6. Fill B, pour water from B to A. Now B has 21-12=9.Empty A, pour the water from B into A. Now A has 9 and can still accept 13-9=4.

7. Fill B, pour water from B to A. Now B has 21-4=17 ounce. We're done.

yes , u r write, but use spoilers next time, remember the blue button you see while posting.

[Guest]

1. Fill flask B, 21 ounce, then pour from B to A, 21-13=8 ounce left in B. Empty A, then pour the water from B to A. Now A has 8 ounce. We can still pour 13-8=5 into A.

2. Fill B, pour water from B to A. Now B has 21-5=16. Empty A, pour the water from B into A. Now B has 16-3=3 left. Empty A. Pour the 3 ounce from B to A. Now A has 3 ounce. Can still have 13-3=10.

3. Fill B, pour water from B to A. Now B has 21-10=11.Empty A, pour the water from B into A. Now A has 11 and can still accept 13-11=2.

4. Fill B, pour water from B to A. Now B has 21-2=19. Empty A, pour the water from B into A. Now B has 19-13=6 left. Empty A. Pour the 6 ounce from B to A. Now A has 6 ounce and can accept 13-6=7 more.

5. Fill B, pour water from B to A. Now B has 21-7=14.Empty A, pour the water from B into A. Now B has 14-13=1 left. Empty A. Pour the 1 ounce from B to A. Now A has 1 ounce and can accept 13-1=12 more.

6. Fill B, pour water from B to A. Now B has 21-12=9.Empty A, pour the water from B into A. Now A has 9 and can still accept 13-9=4.

7. Fill B, pour water from B to A. Now B has 21-4=17 ounce. We're done.

Well done, that is correct!!!

[Guest]

yes , u r write, but use spoilers next time, remember the blue button you see while posting.

Thx for reminding. I'll use it next time. It was my first reply~