Sarah wants to buy the car that has a better mileage rating. Cars of Company A travel 20 miles per gallon, and cars of Company B travel 14 km per liter.

[1 mile = 1.6 km; 1 gallon = 3.79 liters]

Part A: Which company's car should Sarah buy? Justify your answer by comparing the mileages after converting to the same units. (5 points)

Part B: If 10 gallons of gas is filled in the car which gives better mileage and you went on a drive and checked on the gas used every 30 miles, describe appropriate scales on the x-axis and y-axis to graph the rate at which the car uses gas. (5 points)

Question

Sarah wants to buy the car that has a better mileage rating. Cars of Company A travel 20 miles per gallon, and cars of Company B travel 14 km per liter.

[1 mile = 1.6 km; 1 gallon = 3.79 liters]

Part A: Which company's car should Sarah buy? Justify your answer by comparing the mileages after converting to the same units. (5 points)

Part B: If 10 gallons of gas is filled in the car which gives better mileage and you went on a drive and checked on the gas used every 30 miles, describe appropriate scales on the x-axis and y-axis to graph the rate at which the car uses gas. (5 points)

anonymous · Answer

Aim: to assess which has the better mileage rating.
Given:Cars of Co. A travel 20 mile/gallon. Cars of Co.B travel 14km per litre.
Given:  1 mile = 1.6km; 1 gallon = 3.79 litres. 
Solution: since we are asked about 'mileage', lets convert Co. B to miles.
Now since 1 mile = 1.6 km 
dividing both sides by 1.6 we get:
then 0.625 miles = 1 km
therefore 14km = 0.625m x 14 = 8.75 miles

galacticplunder · Answer

Ok, so car #2 would be 8 mpg?

anonymous · Answer

We now know that Co.A does 20 miles/gallon, and Co.B does 8.75miles/litre. 
burt we are given: 1 gallon = 3.79 litres. 
So, if Co. B used 1 gallon (i.e.3.79 litres), they would do 3.79 x 8.75 miles = 33.1625 miles.

i.e Co.A Does 20 miles/gallon and Co.B does 33.1625 miles per gallon.

galacticplunder · Answer

I get it now! Thanks! Could you help me with part B?

anonymous · Answer

"Gas", the american phrase for "petrol". lol

anonymous · Answer

Firstly, we have already determined "the car which gives better mileage" (i.e. car from Co.B)
We know it does 33.1625 miles per gallon. In part B, we are told it was filled with 10 gallons, therefore it can do 10 x 33.1625miles = 331.625 miles (shift the decimal point one place to the left to multiply by 10). so your x axis (which is miles) should go to about 340miles. And your y axis (no.of gallons) should at least be 10.

galacticplunder · Answer

Thank you so much! Sorry this is my first question, how do I reward you?

anonymous · Answer

just click on best response beside one of my answers

anonymous · Answer

you got it, thanks!

galacticplunder · Answer

No problem!

anonymous · Answer

Any other problems, feel free to contact me!