Answer: With 7 gallons of gas, the car can travel 147 miles.
The proportion is:
N*(63 miles/3) = total distance the car can travel with N gallons of gas.
Explanation:
We know that with 3 gallons of gas, the car can travel 63 miles.
Then for N gallons of gas, we first need to count the number of times that 3 is in N.
This is equal to the quotient between N and 3:
N/3
This is the number of times that we have 3 gallons of gas, in a total of N gallons of gas.
And for each one of these, the car can travel 63 miles.
Then the total distance that the car can travel with N gallons of gas is:
(N/3)*63 miles. = N*(63 miles/3) = total distance the car can travel.
In this case, we want to know how many miles the car can travel with 7 gallons of gas, then if we use that equation we get:
(7/3)*63 miles = 147 miles.