Suppose your car gets 36 miles per gallon of gasoline, and you are driving 45 miles per hour. Using unit analysis, find the number of hours it takes to use 1 gallon of gas.
I got 48 minutes but I'm not sure.
1 h/45 mi * 36 mi/1 g
mi cancels and you are left with 36/45 hours/gallon
You wouldn't multiply that answer by 60 ?
36/45 is .8
It is in hours and it asks for hours.
If you wanted minutes you would multiply by 60 min/h to cancel the h and get min/gal but it did not ask for that.
Okay got it. Thank you..
To find the number of hours it takes to use 1 gallon of gas, you need to use unit analysis.
Given:
- The car gets 36 miles per gallon of gasoline.
- You are driving at a speed of 45 miles per hour.
We can convert the given rate of mileage (36 miles per gallon) to hours per gallon, by dividing the mileage rate by the speed rate.
Step 1: Start with the given information:
- rate: 36 miles per gallon
- rate: 45 miles per hour
Step 2: Create conversion factors to convert units:
- 45 miles/1 hour
- 1 gallon/36 miles
Step 3: Set up the unit analysis equation, multiplying the conversion factors to cancel out the unwanted units:
- (1 gallon/36 miles) * (45 miles/1 hour)
Step 4: Simplify the units:
- The miles in the numerator and denominator cancel out leaving only the desired units:
- 45 miles/36 miles
Step 5: Solve the equation:
- 45 miles/36 miles = 1.25 hours
Therefore, it takes 1.25 hours (or 1 hour and 15 minutes) to use 1 gallon of gas.