At the grocery store, you can purchase lemons at 2 for $0.99. you can also buy a bag of 6 lemons for $2.50. Which is the better buy?

Purchasing the bag of 6 lemons is the better buy.

Step-by-step explanation:

There are two ways that we can do this: find the unit rate or find how the LCM.

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The first way is more orthodox, and you should definitely use it in harder problems. We can set up two ratios like so.

2 : 0.99

6 : 2.5

Let's simplify the ratios so the left side is one.

2 : 0.99 = 1 : 0.495 by dividing both sides by 2.

6 : 2.5 = 1 : 0.41666... by dividing both sides by 6.

Comparing the two ratios, we can conclude that the second one is smaller, therefore the bag of 6 lemons costs less.

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The second way, although not very efficient with big numbers, works well with small numbers like these.

First, we need to find the LCM, or the least common multiple. The LCM of 2 and 6 is 6, as 6 is a multiple of both 2 and itself.

Now we must make the amount of lemons match each other so we can compare the price.

2 : 0.99 = 6 : 2.97 by multiplying by 3.

The second ratio stays the same.

2.50 is smaller than 2.97, so the second ratio is smaller than the first, reaching our previous conclusion.

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I hope this helps, let me know if you need any more clarification.