Question

A tourist purchases a car in england and ships it home to the united states. the car sticker advertised that the car's fuel consumption was at the rate of 40 miles per gallon on the open road. the tourist does not realize that the u.k. gallon differs from the u.s. gallon: 1 u.k. gallon = 4.545 963 1 liters 1 u.s. gallon = 3.785 306 0 liters for a trip of 738 miles (in the united states), how many gallons of fuel does (a) the mistaken tourist believe she needs and (b) the car actually require?

Answer 1

Solution-

Fuel consumption rate = 40 miles per UK gallon (As the car is manufactured in UK)

1 UK gallon = 4.5459631 lit

1 US gallon = 3.7853060 lit

$\therefore \frac{1 \ UK \ gallon}{1 \ US \ gallon} = \frac{4.5459631}{3.7853060} = 1.2009499$

$\Rightarrow 1 \ UK \ gallon = 1.2009499 \ US \ gallon$

As the fuel consumption rate = 40 miles per gallon

⇒ You need 1 UK gallon of fuel to go 40 miles

⇒ You need 1.2009499 US gallon of fuel to go 40 miles

Or you can say that, to go 40 miles you need 1.2009499 US gallon of fuel

⇒ To go 1 mile you will need  $\frac{1.2009499}{40} = 0.0300237$

⇒ To go 738 miles you will need 0.0300237×738 = 22.1574906 US gallon of fuel

∴ 22.1574906 gallon of fuel is actually required.

∴ But, what she thinks will require is $\frac{738}{40} = 18.45 gallons$ (As she calculated using UK gallons)