33 of 55 shoppers pay by card. About how many of 2,200 pay by card?

Step by step

The question

Question: 33 of 55 shoppers pay by card.

About how many of 2,200 pay by card?

1 The fraction in the sample

33 out of 55: that is 33/55.

The 55 shoppers are a sample: a small group that stands for everyone.

33 and 55 can both be divided by 11.

So it is 3/5.

2 Use it for everyone

We expect the same fraction of all 2,200: 3/5 of 2,200.

Of means times.

2,200 divided by 5 is 440.

Then times 3.

That is about 1,320.

Careful!

A sample only shows about how many.

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

So about 1,320 shoppers pay by card.

3 Check

Let's check: 1,320 out of 2,200.

Divide the top and the bottom by 440: 3/5, 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.