Calculate $4 for 8 eggs or $9 for 20 eggs

Step by step

The question

Question: which is the better buy, A: $4 for 8 eggs, or B: $9 for 20 eggs?

The amounts are different, so we can't just look at the prices.

We find the price for 1 egg in each deal.

1 Write both as fractions

We write each deal as a fraction.

The money goes on top.

The eggs go on the bottom.

2 Divide to get 1 at the bottom

We want 1 egg on the bottom.

In A, we divide the top and the bottom by 8.

In B, we divide them by 20.

4 divided by 8 is 0.5.

9 divided by 20 is 0.45.

So A is 50 cents per egg.

B is 45 cents per egg.

3 Compare

45 cents is less than 50 cents.

Deal B costs less for each egg.

So deal B is the better buy.

Let's look back.

First: write both as fractions.

Then: divide to get 1 at the bottom.

Last: compare.