Question

The Blakely family has driven 50 miles of a 200-mile trip. Their car travels 30 miles per gallon of gas. How many gallons of gasoline, g, will the car use on the remainder of the trip?

Answer 1

Answer: 5 gallons

Step-by-step explanation: 200 is your total. You start with 50 and the car travels 30 miles per gallon so in the equation it should look like 30g. All together it should look like this 200=50+30g.

From here you slove by subtract 50 from both sides and get:

200 - 50 = 150

50 - 50 = 0

150 = 30g

Then you divide on both sides to get g or gallons alone.

150 / 30 = 5

30 / 30g = g

5 = g

Final answer is 5 gallons

Answer 2

Total gallons needed
1 gallon / 30 miles * 200 miles = 20/3  gallons = 6.67 gallons

gallons used so far : 
1 gallon /  30 miles *  50 miles  = 5/3 gallons = 1.67 gallons

remainder  : 
20/3 - 5/3 = 15/3 = 5 gallo