# Mrs. Cally needs 9 lengths of material to make some drapes. Each length must be 3.5 metres.a)Calculate the total length of material needed. The material cost $5.00 per metre . b)what is the cost of...

**Mrs. Cally needs 9 lengths of material to make some drapes. Each length must be 3.5 metres.**

**a)Calculate the total length of material needed.**

**The material cost $5.00 per metre .**

**b)what is the cost of the material?**

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### 3 Answers

Let's look at (a) first:

**Calculate the total length needed**.

It may be easiest to draw a picture to help you solve this if you're having trouble.

Mrs. Calley will have** 9 lengths** of material:

__________________

__________________

__________________

__________________

__________________

__________________

__________________

__________________

__________________

The problem says that **each "length" is 3.5 meters**. So, for each length that we drew right there, we know they're all going to be 3.5 meters:

__________________ = 3.5 m

__________________ = 3.5 m

__________________ = 3.5 m

__________________ = 3.5 m

__________________ = 3.5 m

__________________ = 3.5 m

__________________ = 3.5 m

__________________ = 3.5 m

__________________ = 3.5 m

Now, we want to find our total length. Maybe you'll notice that you can just **add up all of the lengths** above, and that would work! The easier way, though, would be to **multiply**:

`3.5 (9) = 31.5`

You get the **same result **by adding up the 9 3.5's (which, recall is the original definition of multiplication!).

So, we have our answer for (a): **31.5 meters**

Moving on:

(b) Given the cost of **$5.00 per meter, what is the total cost?**

Well, we have **31.5 meters**, and **each meter costs $5.00**. Again, if this concept doesn't make much sense to you, draw a picture!

____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m

____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m

____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m

____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m

____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m

____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m ____ = 1 m

____ = 1 m __ = `1/2` m

Now, remember, that each meter costs $5.00, so we're just going to write "$5.00" instead of "1 m" next to each picture:

____ = $5 ____ = $5 ____ = $5 ____ = $5 ____ = $5

____ = $5 ____ = $5 ____ = $5 ____ = $5 ____ = $5

____ = $5 ____ = $5 ____ = $5 ____ = $5 ____ = $5

____ = $5 ____ = $5 ____ = $5 ____ = $5 ____ = $5

____ = $5 ____ = $5 ____ = $5 ____ = $5 ____ = $5

____ = $5 ____ = $5 ____ = $5 ____ = $5 ____ = $5

____ = $5 __ = $2.50

Notice, that last one will be half of $5.00 because it is only half a meter.

So, just like above, we can either add everything up, which works! But that takes a while! So, I'm going to go back to the definition of multiplication (again) and just multiply 31.5 meters by $5.00 per meter:

`31.5 * 5.00 = 157.50`

So, our total price will be $157.50. And we're done!

I hope that helped! I know those pictures were a bit crummy, but if they helped, you should draw them on your own paper for yourself!

**Sources:**

**Mrs. Cally needs 9 lengths of material to make some drapes. Each length must be 3.5 metres.**

**a)Calculate the total length of material needed.**

**The material cost $5.00 per metre .**

**b)what is the cost of the material?**

`9xx3.5= 31.5` she need **31.5** metres in total

since the material is $5 per meter just multiply the total by 5

31.5 x 5 = 157.5

so the material will cost **$157.50**

**Mrs. Cally needs 9 lengths of material to make some drapes. Each length must be 3.5 metres.**

**a)Calculate the total length of material needed.**

**The material cost $5.00 per metre .**

**You need to multiply the 9 drapes you need by the length of 3.5 metres**

**9*3.5=31.5 meters**

**or**

**3.5(9)=31.5**

**b)what is the cost of the material?**

**Now you need to multiply your total number of metres (31.5) by $5**

**31.5*$5.00=$157.50 **

**Or **

**31.5*5.=157.50**

**Your material will cost you $157.50!**