
Differentiate both sides wrt
:

By the chain rule, we get


Solve for
:


I believe the answer would be $13,320.
Hope this helps ;}
Because we know the midpoint is in the middle, we know that both sides are equal.
So set both = to each other
4x - 1 = 3x + 3
add 1 to both sides
4x=3x+4
then subtract 3x from both sides and because there is always a 1 in front of x the answer would be
x=4
So you divide 0.8 by 6.25 and your answer is 7.8125 and then you add 5.5 minutes of your other number and you get the answer of 13.3125