1 |
12 |
9 |
20 |
=
1 |
2 |
9 |
20 |
=
1 |
20 |
甲用的時(shí)間:1÷
1 |
20 |
乙的效率:
9 |
20 |
1 |
12 |
=
9 |
20 |
5 |
12 |
=
27 |
60 |
25 |
60 |
=
1 |
30 |
乙用的時(shí)間:1÷
1 |
30 |
答:?jiǎn)为?dú)開(kāi)甲管20小時(shí)注滿,單獨(dú)開(kāi)乙管30小時(shí)注滿.
9 |
20 |
1 |
12 |
9 |
20 |
1 |
2 |
9 |
20 |
1 |
20 |
1 |
20 |
9 |
20 |
1 |
12 |
9 |
20 |
5 |
12 |
27 |
60 |
25 |
60 |
1 |
30 |
1 |
30 |