Roselyn is driving to visit her family, who live $150$ kilometers away. Her average speed is $60$ kilometers per hour. The car's tank has $20$ liters of fuel at the beginning of the drive, and its fuel efficiency is $6$ kilometers per liter. Fuel costs $0.60$ dollars per liter. $\newline$ What is the price for the amount of fuel that Roselyn will use for the entire drive? $\newline$ $\square$ dollars

Full solution

Q. Roselyn is driving to visit her family, who live

150

kilometers away. Her average speed is

60

kilometers per hour. The car's tank has

20

liters of fuel at the beginning of the drive, and its fuel efficiency is

6

kilometers per liter. Fuel costs

0.60

dollars per liter.

\newline

What is the price for the amount of fuel that Roselyn will use for the entire drive?

\newline

\square

dollars

Calculate Total Distance: First, calculate the total distance to find out how many liters of fuel Roselyn will use. $\text{Distance} = 150 \text{ kilometers}.$
Calculate Fuel Needed: Next, calculate the fuel needed by dividing the distance by the fuel efficiency. Fuel needed = $\frac{\text{Distance}}{\text{Fuel efficiency}} = \frac{150 \, \text{km}}{6 \, \text{km/l}}$ .
Divide to Find Fuel Needed: Do the division to find out the fuel needed. Fuel needed = $\frac{150 \, \text{km}}{6 \, \text{km/l}} = 25 \, \text{liters}.$
Calculate Total Cost: Now, calculate the cost of the fuel used by multiplying the fuel needed by the cost per liter. Total cost = $\text{Fuel needed} \times \text{Cost per liter} = 25 \text{ liters} \times 0.60 \text{ dollars/liter}.$
Multiply to Find Total Cost: Finally, do the multiplication to find the total cost. Total cost = $25 \, \text{liters} \times 0.60 \, \text{dollars/liter} = 15 \, \text{dollars}.$