1 |
15 |
1 |
20 |
1 |
25 |
(1)(1-
1 |
15 |
1 |
25 |
=(1-
3 |
15 |
1 |
25 |
=
12 |
15 |
=20(天);
答:還要20天完成.
(2)(
1 |
15 |
1 |
20 |
1 |
25 |
=(
20 |
300 |
15 |
300 |
12 |
300 |
=
47 |
300 |
=
47 |
50 |
47 |
50 |
答:三人合干6天,不能完成這項工程.
1 |
15 |
1 |
20 |
1 |
25 |
1 |
15 |
1 |
25 |
3 |
15 |
1 |
25 |
12 |
15 |
1 |
15 |
1 |
20 |
1 |
25 |
20 |
300 |
15 |
300 |
12 |
300 |
47 |
300 |
47 |
50 |
47 |
50 |