How do you solve this i think its dealing witha a unite rate or an expression?

Question

you are getting ready to make a 640-mile car trip. in general, your car can drive 160 miles on 5 gallons of gasoline. how many gallons of gasoline willl you use for the trip? you started out with 4 gallons of gasoline in your car is $2.29 per gallon. how much money will you spend on gasoline on the trip?

can you help me solve this and explain plz

Answer 1

For the first part I would use ratios:

5/160 = x/640

Solve for x to get the number of gallons.

Next you can use this equation:

(x-4) * 2.29 = m

x from above.

m = money