15,840 is the answer for this question.
1:500000
1cm:500000cm
2:250000
2cm:250000cm
1cm:125000cm
To get this you convert the km into cm as it is easier and then it becomes something like this 2cm : 250000cm
then divide or half to get to the simpler form like this 2cm divided by 2=1cm and 250000cm divided by 2= 125000cm
then put into ratio is 1:125000
