Answer:
endpoint is (29, -13)
Step-by-step explanation:
Formula for midpoint is 
So, let
be the coordinates of the endpoint you are looking for.
and
= (10, -3)

-9 +
= 20 7 + 

endpoint is (29, -13)
-64 + -4 = -68
That is because 64 + 4 = 68 and the negatives in this case are the same way as if it was all positive.
Neither, they both have the same amount of battery.
Explanation: Stella is 4/6 charged. Stanley is 2/3 charged. When 4/6 is reduced, the equivalent fraction is 2/3.