bob's car rental company makes you pay 10 dollars per day you rent the car and a 30 dollar insurance fee
joe's car rental company makes you pay 30 dollars per day you rent the car and a 10 dollar insurance fee
how many days do you need to rent a car for the cost for renting both are the same
bob=10x+30
joe=30x+10
set each to each other
10x+30=30x+10
subtract 10x
30=20x+10
subtract 10
20=20x
divide both sides by 20
1=x
you need to rent 1 day for them to be equal