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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txmedteach's profile pic

txmedteach | High School Teacher | (Level 3) Associate Educator

Posted on

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:
atyourservice's profile pic

atyourservice | Student, Grade 11 | (Level 3) Valedictorian

Posted on

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

yayahelligan's profile pic

yayahelligan | College Teacher | (Level 1) eNoter

Posted on

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!

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