=225 km
The sum of the speeds of car A and car B: 225 ÷ 6 = 37.5km.
Express speed: 37.5× 8/(8+7) = 20km.
Idle speed: 37.5× 7/(8+7) =17.5km.
A: The speed of the express train is 20km/h and the speed of the local train is17.5km/h..
2. Arithmetic method:
With 200 grams of seawater, 7 grams of salt can be dried, indicating that salt accounts for 7/200 of salt water, so the dried salt is 7/200 of 103600.
103600×7/200=3626 tons
Use proportional solution:
Solution: Suppose 103600 tons of seawater can produce X tons of salt.
X: 103600=7:200
200X = 103600×7
X =3626
A: 103600 tons of seawater can produce 3626 tons of salt.
3. The line segment scale is a line segment marked with (number) on (map) to indicate the corresponding (actual distance) on the ground.