In a sample of 80 apples, 6 were bad. About how many of 1,200 are bad?

Step by step

The question

Question: In a sample of 80 apples, 6 were bad.

About how many of 1,200 are bad?

1 The fraction in the sample

6 out of 80: that is 6/80.

The 80 apples are a sample: a small group that stands for everyone.

6 and 80 can both be divided by 2.

So it is 3/40.

2 Use it for everyone

We expect the same fraction of all 1,200: 3/40 of 1,200.

Of means times.

1,200 divided by 40 is 30.

Then times 3.

That is about 90.

Careful!

A sample only shows about how many.

So the answer is a good guess, not an exact count.

So about 90 apples are bad.

3 Check

Let's check: 90 out of 1,200.

Divide the top and the bottom by 30: 3/40, the same fraction as the sample.

So the answer is right!

Let's look back.

First: the fraction in the sample.

Then: use it for everyone.

Last: check.