AAaaahh yes, T'was that a lovely chap by the name of Copernicus, has discovered us a little secret, well. why dont you share?
Copernicus: well uh, i'm a bit shy
ME: who a gives a flying *bleep* about your feelings man! just man up an discover the earth's rotation already!
Let v = the running speed
After running at constant speed for 26 min, the distance traveled is
d = (v m/min)*(26 min) = 26v m
Because there are 1500 m to go, the distance traveled is
10000 - 1500 = 8500 m
The running speed is
v = (8500 m)/(26 min) = 326.9 m/min
In km/h, the speed is
v = (0.3269 km/min)*(60 min/h) = 19.6 km/h
Answer: The running speed is 19.6 km/h
The graph is one single line and, as a system solution refers to an intersection point (in other words, a point in common), we affirm both equations share all of their points and thus, such system has infinite solutions.
Because they are conducting, when you bring them together the charge is split equally among the two spheres (because they have the same radius the amount of charge is also equal). Now they will repel each other because of the net charge on each with the same polarity.