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1 year ago

Sean is a bookworm. On average, he reads pages in minutes.

Mathematics

1 answer:

yulyashka [42]1 year ago

8 0

For example:
5 pages in 10 minutes

Per minute: 5/10 = 0.5 pages in 1 minute or half a page

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18. Manufacturers often package products in a way that uses the least amount of material One measure of the efficiency of a pack

Lemur [1.5K]

Answer:

a. $E=\frac{2h+2r}{rh}$

E of first can = $E=\frac{2h+2r}{rh}$

E of second can = $E=\frac{h+2r}{rh}$

c. Yes

Step-by-step explanation:

The efficiency ratio is:

E = Surface Area / Volume

We can write:

$E=\frac{S}{V}$

Where

S is surface area of cylinder

V is volume of cylinder

The formulas are:

S = $2\pi rh+2\pi r^2$

V = $\pi r ^2 h$

So, the <u>efficiency ratio (E) </u>is:

$E=\frac{2\pi rh+2\pi r^2}{\pi r^2 h}\\E=\frac{\pi r(2h+2r)}{\pi r(rh)}\\E=\frac{2h+2r}{rh}$

The first can has radius "r" and height "h", so the efficiency ratio is:

$E=\frac{S}{V}\\E=\frac{2\pi rh+2\pi r^2}{\pi r^2 h}\\E=\frac{\pi r(2h+2r)}{\pi r(rh)}\\E=\frac{2h+2r}{rh}$

The second can has same height, "h", and twice radius, "2r", so the efficiency ratio becomes:

$E=\frac{S}{V}\\E=\frac{2\pi (2r)h+2\pi (2r)^2}{\pi (2r)^2 h}\\E=\frac{4\pi rh +8\pi r^2}{4\pi r^2h}\\E=\frac{4\pi r(h+2r)}{4\pi r(rh)}\\E=\frac{h+2r}{rh}$

We now need to say if the company made a good decision or not.

If you look at both the Efficiency ratios above, you will see that the difference is in the numerator.

The first can has "2h"

The second can has "h"

The "2h" makes the numerator for the first can BIGGER than the "h" of the second can, so the Efficiency ratio of first can is thus, BIGGER.

We need smaller ratio.

So, 2nd can has indeed smaller ratio, so the company made a good decision.

6 0

2 years ago

Which subtraction expression does the number line model show

loris [4]

Answer:

13-+4

Step-by-step explanation:

3 0

1 year ago

The means and mean absolute deviations of the individual times of members of two relay swim teams are shown in the table below.

shepuryov [24]

See the attached picture for the solution:

7 0

1 year ago

Read 2 more answers

Which expressions are equivalent to -6n+(-12)+4n

muminat

Answer:

i THINK its A. 4(n-3) -6n

Step-by-step explanation:

Have a wonderful day!!

6 0

1 year ago

A heap of rubbish in the shape of a cube is being compacted into a smaller cube. Given that the volume decreases at a rate of 3

inna [77]

Answer:

-1/4 meter per minute

Step-by-step explanation:

Since, the volume of a cube,

$V=r^3$

Where, r is the edge of the cube,

Differentiating with respect to t ( time )

$\frac{dV}{dt}=3r^2\frac{dr}{dt}$

Given, $\frac{dV}{dt}=-3\text{ cubic meters per minute}$

Also, V = 8 ⇒ r = ∛8 = 2,

By substituting the values,

$-3=3(2)^2 \frac{dr}{dt}$

$-3=12\frac{dr}{dt}$

$\implies \frac{dr}{dt}=-\frac{3}{12}=-\frac{1}{4}$

Hence, the rate of change of an edge is -1/4 meter per minute.

4 0

1 year ago