Six pens cost $4.80. Each pen costs the same. What is the cost of…

Step by step

The question

Question: $4.80 for 6 pens.

How much for 1 pen?

A unit rate tells us how much for just 1.

Here: dollars for 1 pen.

There are four choices.

First we solve it, the normal way.

Then we pick.

1 Write it as a fraction

We write it as a fraction.

The money goes on top.

The pens go on the bottom.

2 Divide to get 1 at the bottom

We want 1 pen on the bottom.

6 divided by 6 is 1.

We divide the top by 6 too, so the rate stays the same.

4.8 divided by 6 is 0.8.

So it is 80 cents for 1 pen.

Per means for each.

So the unit rate is 80 cents per pen.

3 Check

Let's check: 6 pens at 80 cents per pen.

6 times 0.8 is 4.8.

That is 4 dollars and 80 cents, so it is right!

4 Pick the choice

Our answer is $0.80 per pen.

That is choice A.

5 Why not the others

B is $1.25.

Wrong: 6 ÷ 4.80: upside down; the cost goes on top.

C is $10.80.

Wrong: added 6 instead of dividing.

D is $28.80.

Wrong: multiplied by 6 instead of dividing.

Let's look back.

First: write it as a fraction.

Then: divide to get 1 at the bottom.

Then: check.

Then: pick the choice.

Last: why not the others.