ElectricPavlov

45 ppl / km²   *  33 km²  = 1485 ppl

N = A + 125

J = A/2

N + J + A = (A+125) + A/2 + A = 765   

                 a+125    + a/2   + a    = 765

                  2.5 a = 765 - 125

                       a = 256          n = 256 + 125 =381            j = 256/2   = 128
 

5012 km  /  7hr   =   716 km/hr

896   -   ( 7 *58 )    =   white balls

Answers look OK to me !  

I think the base is the line with an arrow with no dimension.       (changed )

j = 5r

j- s  = r + s

5r-s = 9      s = 'some stickers'

r+s = 9       add these two equations

6r = 18

r = 3               then           j = 5r = 15      

r + s = 9

3 + s = 9

s = 6

Twenty four

Here is the graph....the point where the two graphs intersec is the solution to the system of equations:

7200 sec  /  (3600 sec/hr) = 2 hrs

2:30 pm + 2 hrs = 4:30 PM