Answer:
1,778
Step-by-step explanation:
Let C and S represent the cost and salvage value of Truck B, respectively. Let X represent the number of miles per year that answers the question.
Truck A's cost for 10 years is ...
A = C+600 +(0.06)(2.25)(10X) -(S+200)
Truck B's cost for 10 years is ...
B = C +(0.07)(2.25)(10X) -S
We want to find X such that Truck A's cost is lower, so ...
C -S +1.35X +400 < C -S +1.575X
400 < 0.225X
1777 7/9 < X
1778 miles driven per year (or more) makes Truck A a better option.