解:(1)30%x+50%x=15, | |||||||||||||||||
80%x=15, 80%x÷80%=15÷80%, x=
(2)25-10%x=5, 25-10%x+10%x=5+10%x, 5+10%x-5=25-5, 10%x÷10%=20÷10%, x=200; (3)90%X-20%=125%, 90%X-20%+20%=125%+20%, 90%X÷90%=145%÷90%, x=
(4)90%X÷
| |||||||||||||||||
90%X÷
90%X÷90%=
x=
(5)75%÷25%X=20%, 75%÷25%X×25%x=20%×25%x, 20%×25%x÷20%=75%÷20%, 25%x÷25%=
|
5 |
2 |
2 |
3 |
1 |
2 |
7 |
5 |
2 |
3 |
1 |
2 |
1 |
2 |
7 |
5 |
1 |
2 |
2 |
3 |
2 |
3 |
19 |
10 |
2 |
3 |