On a map with a scale of 1:3000000, the distance between a and B is 15cm

On a map with a scale of 1:3000000, the distance between a and B is 15cm

Actual distance = 15x3000000 = 45000000 cm = 450 km

On a map with a scale of 1:3000000, the distance between a and B is 4cm. On a map with a scale of 1:800000, the distance between the two places is larger
On a map with a scale of 1:3000000, the distance between a and B is 4cm. If you draw on a map with a scale of 1:800000, what is the distance between the two places

3000000X4/800000=15cm

Formula
On a map with a scale of 1:3000000, the distance between AB and ab is measured to be 9.6cm. A and B vehicles run from AB and meet each other in 4 hours. The speed ratio of a and B vehicles is 5:4. How many kilometers are the speed of a and B vehicles

Actual distance = 9.6 * 3000000 / 100000 km
So speed sum = (9.6 * 3000000 / 100000) / 4
So a [(9.6 * 3000000 / 100000) / 4] * 5 / (4 + 5) = 40 km / h
B [(9.6 * 3000000 / 100000) / 4] * 4 / (4 + 5) = 32 km / h

On a map with a scale of 1:3000000, the distance between a and B is 20cm. On another map, the distance between a and B is 10cm
What is the scale of the other map

Let the distance between a and B be X
So 20: x = 1:3000000
So 10: x = 1:6000000
So the scale of another map is 1:6000000