20 | ( | 30 | + | t | ) | ÷ | 60 | = | 40 | t | ÷ | 80 |
方程左边 = | 1 3 | ( | 30 | + | t | ) |
1 3 | ( | 30 | + | t | ) | = | 40 | t | ÷ | 80 |
方程左边 = | 1 3 | × | 30 | + | 1 3 | t |
= | 10 | + | 1 3 | t |
10 | + | 1 3 | t | = | 40 | t | ÷ | 80 |
方程右边 = | 1 2 | t |
10 | + | 1 3 | t | = | 1 2 | t |
1 3 | t | − | 1 2 | t | = | - | 10 |
- | 1 6 | t | = | - | 10 |
10 | = | 1 6 | t |
1 6 | t | = | 10 |
t | = | 10 | ÷ | 1 6 |
= | 10 | × | 6 |
t | = | 60 |