Final answer:
The unit rate for the student's deal ($61.05 for 20 gallons) is $3.0525 per gallon. Upon comparison with the given options, the better deal is $1.00 per gallon for 800 million gallons, as it is the lowest unit rate available.
Step-by-step explanation:
The student seeks to determine the unit rate of the better deal for purchasing gasoline. The unit rate is calculated by dividing the total cost by the quantity of units purchased. In this case, the units are gallons of gas.
To find the unit rate of the deal offered ($61.05 for 20 gallons), we would perform the following calculation:
Unit rate = Total cost / Total gallons
Unit rate = $61.05 / 20 gallons = $3.0525 per gallon
However, to ascertain the better deal from the options given, we must compare this unit rate with the rates offered:
- $1.00 per gallon, 800 million gallons
- $1.20 per gallon, 700 million gallons
- $1.40 per gallon, 600 million gallons
- $1.60 per gallon, 550 million gallons
- $1.80 per gallon, 500 million gallons
- $2.00 per gallon, 460 million gallons
- $2.20 per gallon, 420 million gallons
Since all the given rates from the list are better (lower) than $3.0525 per gallon, the student should choose the lowest unit rate from the list, which is $1.00 per gallon for 800 million gallons as the better deal.