Question

your family needs to rent a car for a week while on vacation. company B charges $3 per mile plus a flat fee of $150 per week. company D charges $4 per mile plus a flat fee of $75 per week

Answer 1

I'm assuming, find how many miles to drive before both companies are equal

1 week total so

B=3m+150
D=4m+75

find when equal
150+3m=4m+75
minus 3m both sides
150=m+75
minus 75 both sides
75=m

must drive 75miles before cost of both companies are equal