GED Mathematical Reasoning TestQuantitative Problem Solving with Rational NumbersMedium
A car travels 324 miles on 12 gallons of gasoline. At this rate, how many miles can the car travel on 7 gallons of gasoline?
- A189 miles
- B270 miles
- C216 miles
- D243 miles
Show answer & explanationAnswer & explanation
Correct answer: A. 189 miles
First, find the car's miles per gallon (MPG): 324 miles / 12 gallons = 27 MPG. Then, multiply the MPG by the new amount of gasoline: 27 MPG * 7 gallons = 189 miles.
Why the other options are wrong
- B. This is incorrect; it might be a miscalculation of the rate or the final product.
- C. This is incorrect; it might be a miscalculation of the rate or the final product.
- D. This is incorrect; it might be a miscalculation of the rate or the final product.
Unit Rate and Proportionality
A unit rate expresses how much of one quantity there is per one unit of another quantity. Proportionality means that two quantities have a constant ratio.
- Unit Rate = Total Quantity / Total Units.
- Can be used to scale quantities up or down.
- Often involves division to find the rate, then multiplication to scale.
Memory trick: Rate first, then multiply, for how far or how much, don't be shy.