Carson runs a carpool for five of his friends. The five of them cover all the gas expenses to compensate Carson for his time. Their total commute is 21 miles one way, gas costs $2.50/gallon, Carson's car gets 30 miles/gallon, and they commute to work 5 days a week, 4 weeks a month. How much does each person pay toward gas monthly?
Let's be accurate as possible and think first.
14
First find the total number of monthly commutes: 5 days / week * 4 weeks / month = 20 days / month.

Then multiply the distance of the commute one way by the two ways: 21 miles * 2 = 42 miles.

Then multiply the number of commutes by the number of miles per commute: 42 miles / commute * 20 commutes = 840 miles.

Then divide the number of miles by the car's gas mileage: 840 miles / 30 miles / gallon = 28 gallons.

Then multiply that number by the cost of each gallon to find the total cost: 28 gallons * $2.

50 / gallon = $70.

Then divide the total cost by the number of friends to find the cost per person: $70 / 5 people = $14 / person.

.

The final answer: 14