3.7cm on the map represents 1850km in reality
3.7cm : 1850km
1cm : 1850/3.7 km
1cm : 500km
Scale statement for map is : 1cm : 500km.
That is 1cm on map represents 500km.
1cm : 500km. Recall 1km = 1000m = 100 000cm
1cm : 500* 100000cm
1cm : 50 000 000cm
1: 50 000 000.
Scale factor is 50 000 000.
If you times -3 by -5 the negatives cancel eachother and therefore you get 15.
The answer to your problem is 7/10=0.7
7/10 as a decimal is 0.7