Hi again 315. :)
Say the average round distance for Haul A is X miles
Then the average round distance for Haul B will be
60%*(x+5) + 20%*(X-2) +20%*X
=0.6X + 0.6*5 -0.2X - 0.2*2 +0.2X
= X + 0.6*5 - 0.2*2
This question is only concerned with the difference in the average distance so which is
=0.6*5 - 0.2*2
= 3 - 0.4
= 2.6 miles The average truck will travel 2.6miles further per load for plan B
Now I think that there are too many things that are poorly worded or not explained in this question BUT
this is my take.
What is the extra cost for part A.
I have to assume that the $2.35 / m^3 includes transport and material costs.
2.35*2*10^6 = 4.7*10^5 = 4.7 million dollars
Extra costs for area A is 4.7 million dollars
Now what are the extra costs for part B
Q how many truck loads will it take to fill the 14*10^6 m^3 tip
A 14*10^6 divided by 20 = 7*10^5 loads
Q and how many extra distance will this be for B?
A 2.6*7*10^5 = 1.82*10^6 miles
Q At 15mph how much extra time will this take?
A 1.82*10^6 divided by 15 = 121333 and 1/3 hours
Q At $35 pr hour how much extra cost will this be?
A 121333 and 1/3 hours *35 = $ 4246666.67
Extra Cost for area B is 4.245 million dollars
Extra costs for area A is 4.7 million dollars
So, based on the information given, area B is cheaper.