A car uses 15 gallons of gaz to travel 300 miles. How many gallons are needed for this car to travel a distance of 430 miles?

To determine how many gallons are needed for the car to travel a
distance of 430 miles, we'll have to use the rule of three.

15
gallons...........................300 miles

x
gallons..............................430 miles

We'll cross
multiply:

x*300 = 15*430

x =
15*430/300

x = 15*43/30

x 
=43/2

x = 21.5 gallons

Therefore,
the car needs 21.5 gallons to travel 430 miles.