The two trains leave from a and B and meet at 48km from the midpoint after 4 o'clock. The speed of the slow train is five seventh of that of the fast train. What are the speeds of the fast train and the slow train?

The two trains leave from a and B and meet at 48km from the midpoint after 4 o'clock. The speed of the slow train is five seventh of that of the fast train. What are the speeds of the fast train and the slow train?

Express speed
48×2÷4÷（1-5/7）
=24÷2/7
=84 km / h
Slow speed 84 × 5 / 7 = 60 km / h

A. The distance between B and B is 630 kilometers. A and B start from a and B at the same time, and run in opposite directions. After 9 hours, they meet. It is known that the speed ratio of a and B is 7:3
How many kilometers does a travel more than B when they meet

Solution 1: 630 △ 9 = 70km (the sum of the speed of a and B is 70km)
Because the speed ratio of a and B is 7:3. We divide 70 km into 10 parts, 7 parts for a and 3 parts for B
The speed of a is 7 × 7 = 49 km, and that of B is 7 × 3 = 21 km
The speed difference is 49-21 = 28 km
Distance difference 28 × 9 = 252km

The speed ratio of car a and car B is 4 to 7. The two cars are going from two places at the same time. They meet 15 kilometers away from the destination. How much is car B

It is known that the speed ratio of car a and car B is 4:7. When they meet, car a runs 4 / (4 + 7) = 4 / 11 of the whole journey and car B runs 7 / (4 + 7) = 7 / 11 of the whole journey