While in europe, if you drive 105 km per day, how much money would you spend on gas in one week if gas costs 1.10 euros per liter and your car's gas mileage is 30.0 mi/gal? assume that 1euro=1.26dollar?

You would spend $95.10.

You use a series of conversion factors.

There are many conversions, so let's break it into parts.

Calculate the gallons used

1 week * 7days 1week * 125km 1day * 1mi 1.60934km * 1gal 30.0mi =

18.123 gal (three significant figures plus two guard digits)

Calculate the cost

18.123 gal * 3.78541L 1gal * €1.10 1L * $1.26 €1 = $95.10

The answer has only three significant figures, so it is precise only to the nearest

10 ¢.

Notice how the conversion factors are set up so they cancel to give the desired units at the end.