Understanding unit rates is important for solving everyday problems that involve ratios.

A unit rate is when we compare two different amounts, but we express one of those amounts as one.

For example, let's say a car drives 300 kilometers and uses 15 liters of fuel. We can find the unit rate of how much fuel the car uses like this:

1. Calculate the Unit Rate:

   • To find the unit rate, we take the total fuel used and divide it by the distance traveled:
   • $\text{Unit Rate} = \frac{\text{Total Fuel}}{\text{Distance}} = \frac{15 \text{ liters}}{300 \text{ km}} = 0.05 \text{ liters/km}$
   • This means the car uses 0.05 liters of fuel for each kilometer it travels.

2. Applications in Shopping:

   • When you go grocery shopping, it’s helpful to compare unit prices to find the best deal.
   • For example, if a 500g bag of flour costs 20 SEK and a 1kg bag costs 35 SEK, we can find the unit rates:
     • For the 500g bag:
     • $\text{Cost per gram} = \frac{20 \text{ SEK}}{500 \text{ g}} = 0.04 \text{ SEK/g}$
     • For the 1kg bag:
     • $\text{Cost per gram} = \frac{35 \text{ SEK}}{1000 \text{ g}} = 0.035 \text{ SEK/g}$
   • This tells us that the 1kg bag is a better deal.

3. Other Examples:

   • You can also use unit rates in other situations, like figuring out speed (for example, 60 km/h) or cost per item (like 50 SEK each for 3 items).
   • Using unit rates makes it easier to make decisions in everyday life.
   • This is especially helpful for managing money and saving time.