Why is it better for those maps to use their own grid, instead of latitude and longitude?

How did the korean war impact the elections of 1952?

There are 4 red balls, 6 white balls, and 3 green balls in a bag. if one ball is drawn from the bag at random, what is the probability that it is not white?

Can someone me? i need to have this done as soon as possible! i'm putting 20 points on this!