To solve this problem you must apply the proccedure shown below:
1. You have that Jim drove the car 2,718.3 miles for a total mileage of 87,416.
2. Then, to calculate the mileage before last month, you only need to substract the total mileage given in the exercise above and the mileage drove last month, as following:

Therefore, the answer is: 84,697.7 miles.
Answer: 46 years
Step-by-step explanation:
Let the father's age be x and the son's age be y, then 3 years ago:
Father = x - 3
son = y - 3
Then , from the first statement :
x - 3 = 3 ( y - 3 )
x - 3 = 3y - 9
x = 3y - 9 + 3
x = 3y - 6 .......................................... equation 1
In five years time
father = x + 5
son = y + 5
Then , from the second statement
x + 5 = 2 ( y + 5 )
x + 5 = 2y + 10
x = 2y + 10 - 5
x = 2y + 5 ........................ equation 2
Equating equation 1 and 2 , we have
3y -6 = 2y + 5
add 6 to both sides
3y = 2y + 5 + 6
subtract 2y from both sides
3y - 2y = 11
y = 11
substitute y = 11 into equation 1 to find the value of x
x = 3y - 6
x = 3(11) - 6
x = 33 - 6
x = 27
This means that the father is presently 27 years and the son is presently 11 years.
In four years time
father = 27 + 4 = 31
son = 11 + 4 = 15
sum of their ages in four years time will be
31 + 15 = 46 years
Area of the shaded region=area of the greater rectangle- area of the inner rectangle.
Area of a rectangle=length x width.
Area of the greater rectangle=(8x-1)(6x)
area of the inner rectangle=(5x+3)(2x)
Area of the shaded region=(8x-1)(6x)-(5x+3)(2x)
=48x²-6x-(10x²+6x)
=48x²-6x-10x²-6x
=38x²-12x
Answer: the area of the shaded region would be: 38x²-12x