Answer :
Final answer:
To calculate the number of gallons of gasoline needed for a 2-hour trip at 60 mph with fuel efficiency of 15 km/l, we first convert the trip distance from miles to kilometers, then calculate the liters of gasoline needed, and finally convert to gallons. The result is approximately 3.4 gallons, rounded to two significant figures as 3.5 gallons. Therefore, option A) 3.5 gallons is the correct answer.
Explanation:
The question is asking to calculate the number of gallons of gasoline a car needs for a 2-hour trip, traveling at 60 miles per hour and having a fuel efficiency of 15 kilometers per liter. To find the answer, we need to first calculate the distance traveled in miles, then convert that distance into kilometers before finally converting the fuel consumption into gallons.
First, we calculate the distance traveled in 2 hours at a speed of 60 miles per hour:
- Distance = Speed × Time = 60 miles/hour × 2 hours = 120 miles
Next, we convert the distance from miles to kilometers using the conversion factor that 1 mile is approximately 1.60934 kilometers:
- 120 miles × 1.60934 km/mile = 193.12 kilometers
Then, we determine how many liters of gasoline are needed for 193.12 kilometers:
- Gasoline needed = 193.12 kilometers ÷ 15 kilometers/liter = 12.875 liters
Finally, we convert liters to gallons using the conversion factor that 1 gallon is approximately 3.78541 liters:
- 12.875 liters ÷ 3.78541 liters/gallon = 3.4 gallons
The number of gallons needed is approximately 3.4, which to two significant figures is 3.5 gallons. Therefore, the correct answer is A) 3.5 gallons.
