Question

An unopened cereal box contains `15/28` cubic foot of cereal. If the box is full, and the length and height of the box are `5/7` and `1(1)/(2)` feet, respectively, what is the width of the box?

A.
`1/2` foot
B.
`1/7` foot
C.
`3/5` foot
D.
`4/7` foot
please help

Answer 1

hello AZ

Answer 2

can u help me please

Answer 3

You should know that

Volume = length * width * height

They tell you that an unopened cereal box contains 15/28 cubic feet of cereal

That is the volume

And they tell you that the length is 5/7 feet
And that the height is 1 1/2 or 3/2 feet

And we want to find out the width

Answer 4

So put the numbers into our formula

Volume = length * width * height

15/28 = 5/7 * width * 3/2

can you solve for width?

Answer 5

yes thx

Answer 6

What do you get?

You can first multiply the fractions 5/7 and 3/2

What is 5/7 * 3/2

Answer 7

Remember that

\(\dfrac{a}{b} \times \dfrac{c}{d} = \dfrac{a\times c}{b \times d}\)

Answer 8

?

Answer 9

We have

15/28 = 5/7 * 3/2 * width

we want to solve for width, right?

So first let's simplify it by multiplying the two fractions on the right

Answer 10

so u mean multiply 3/2 and the width

Answer 11

hello?

Answer 12

No

First multiply the length and the height

the length is 5/7 and the height is 3/2

What is 5/7 * 3/2

Answer 13

We then would divide that from the volume to get the width

Answer 14

1.07142857143

Answer 15

that's what i got

Answer 16

Don't use a calculator

Just multiply the top part of the fraction
and the bottom

what is 5 * 3 =
what is 7 * 2 =

Answer 17

15 and 14

Answer 18

Good so that means

\(\dfrac{5}{7} \times \dfrac{3}{2} = \dfrac{5\times 3}{7\times 2} = \dfrac{15}{14}\)

Does that make sense?

Answer 19

So now we have

Volume = length * width * height

15/28 = 5/7 * 3/2 * width

and we said that 5/7 * 3/2 = 15/14 so we get

15/28 = 15/14 * width

Answer 20

Are you following along still?

So what does the width have to be if we're going to multiply 15/14 to make it 15/28

What are we multiply the 14 in the denominator by to get 28?