The number of gallons of fuel Roselyn need for her journey is:
D. 5 gallons
It is given that:
Roselyn wants to drive her car at a speed of 60 miles per hour for 1.25 hours.
This means that the total distance she covers in 1.25 hours is:
[tex]60\times 1.25=75\ \text{miles}[/tex]
( Since, we know that speed is defined as the ratio of distance to time.
i.e.
[tex]Speed=\dfrac{Distance}{Time}\\\\i.e.\\\\Distance=Speed\times Time[/tex] )
Also, Her car has a fuel efficiency of 15 miles per gallon.
i.e.
She could cover 15 miles with 1 gallon of fuel.
Hence, in order to cover 75 miles.
i.e. to cover (15×5) miles she needs (1×5) gallons of fuel
i.e. she needs 5 gallons of fuel to cover 75 miles.
