Would the purchase of a Prius decrease fuel consumption if it is the second car in a household? Let’s face it car pooling even with a person in your family can be inconvenient. A second car makes separate trips convenient. A second car that is a Prius makes second trips inexpensive.
Question: A household with a Honda Pilot travels (21 mpg) travels 15,000 miles per year. After the purchase of a second car the Toyota Prius (42 mpg) the amount traveled per year increases by 15%. What percent of travel must occur in the Prius for this household to realize a decrease in gas consumption?
I need to do a better job documenting my fuel efficiency sources.
I relied on these fuel efficiency numbers in this post:
Fuel efficiency numbers for the Pilot:
Fuel Efficiency numbers for the Prius:
Answer: Prior to the purchase of Prius the household uses 15000/21 or 714.3 gallons of gas.
Denote x amount traveled by pilot and 17250-x amount traveled by Prius.
714.3 = (x/21 + (17250-x)/42)
714.3 x 42 = 2x +17250 –x
30000.6 = x +17250
Plug 12750.6 into expression for fuel efficiency.
((12750.6/21) + (17250-12750.6)/42) is equal to 714.3.
So if the Prius is driven over 26% of the time (17250-127750.6)/17250
fuel consumption will be lower in the Pilot/Prius household than in the Pilot household.