1. The distance between two cities on the map was 6.5 cm. If the scale of the picture is 1:5000000, find the distance between the two cities.
2. How many centimeters can be used to represent a distance of 650 km on a map with a scale of 1:1500000?
3. If the distance between Ulaanbaatar and Choibalsan is 630 km, and the distance between these cities is shown on the map as 7 cm, find the scale of the map.