The distance between a and B is 1920 km. A passenger car and a freight car leave from a and B at the same time. The speed of a passenger car traveling 120 km per hour is 1.5 times of that of a freight car After a few hours, the two cars met?

The distance between a and B is 1920 km. A passenger car and a freight car leave from a and B at the same time. The speed of a passenger car traveling 120 km per hour is 1.5 times of that of a freight car After a few hours, the two cars met?

120 △ 1.5 = 80 (km) freight car speed
120 + 80 = 200 (km) combined speed of passenger and freight cars
1920 △ 200 = 9.6 hours
Comprehensive formula: 1920 ^ (120 + 120 ^ 1.5) = 9.6 (hours)

The distance between a and B is 684 km, and the passenger cars and freight cars leave at the same time. It is known that the freight cars travel 54 dry meters per hour, and the speed ratio between the freight cars and the passenger cars is 9:10. How many hours will it take for the two cars to meet?

6

The ratio of a and B is 4:5. A is a fraction of B. B is a fraction of A
If the sum of a and B is 72, then a is () and B is ().
If the difference between a and B is 0, then a is () and B is ().

Let a be 4 and B be 5,
Then, the number a is 4 / 5 of the number b = 4 / 5
Number B is more than number a (5-4) / 4 = 1 / 4

The number of a is six seventh of the number of B, and the number of B is the number of a, the number of a is less than the number of B, and the number of B is more than the number of a?

According to the condition "the number a is six seventh of the number B", the number B is regarded as the unit "1", then the number a = 1 × 6 / 7 = 6 / 7;
The number B is 1 / 6 / 7 of the number a = 7 / 6;
The number of a is less than that of B (1-6 / 7) △ 1 = 1 / 7;
Number B is more than number a (1-6 / 7) △ 6 / 7 = 1 / 7 △ 6 / 7 = 1 / 6;
Or:
If we take number B as 7, then number a has 6,
The number B is 7 / 6 of the number a = 7 / 6;
The number of a is less than that of B (7-6) △ 7 = 1 / 7;
Number B is more than number a (7-6) △ 6 = 1 / 6