Unit rate to write an equation

Question

A car can travel 476 miles on 14 gallons of gas.  Write an equation relating the distance d to the number of gallons g. How many gallons of gas does this car need to travel 578 miles. 

Answer 1

Jessica.

 

We can set up a proportion

 

476        x

----  =  ----

14          1

 

Cross multiply to solve for x

 

476 = 14x

x = 34 miles per gallon

 

The equation relating distance, d to gallons, g is

d = 34g

 

If the car travels 578 miles

578 = 34g

g = 17

You will need 17 gallons to travel 578 miles at 34 miles per gallon.