The answer is C. 2 hours and 15 minutes. Please refer to the attached document to see the image for better understanding of solution.
Philadelphia = Point A
Pittsburgh = Point B
X = distance traveled by Michelle
(305-X) = distance traveled by Rich
The general formula used is:


Assigning values gives 2 equations:
For Michelle:

For Rich:

Substituting both equations gives:
X = 146.852 miles
t = 2.26 hours or approximately 2 hours and 15 minutes
Answer:
Step-by-step explanation:
Suppose the dimensions of the playground are x and y.
The total amount of the fence used is given and it is 780 ft. In terms of x and y this would be 3x+2y=780 (we add 3x because we want it to be cut in the middle). Therefore, y= 780/2-3/2x. Now, the total area (A )to be fenced is
A=x*y= x*(390-3/2x)=-3/2 x^2+390x
Calculating the derivative of A and setting it equals to 0 to find the maximum
A'= -3x+390=0
This yields x=130.
Therefore y=780/2-3/2*130=195
Thus, the maximum area is 130*195=25,350ft^2
Group and factor
group y's with y's and z's with z's
(y²-10y)+(10z-yz)
factor
y(y-10)+z(10-y)
force undistribute -1
-y(10-y)+z(10-y)
factor
(10-y)(-y+z)
(z-y)(10-y) or
(y-z)(y-10)
Answer: At least 13
Step-by-step explanation:
10x-(3x7-3x2x)+18
10x-(21-3x2x)+18
10x-(21-6x)+18
10x-21+6x+18
16x-21+18
16x-3