Ask question

Ask question

All categories

3 years ago

8

The school store sells 18 folders for $4.50. Select the three unit rates that describe this sale. $0.25 per folder , 4 folders p

er dollar ,36 folders per $9, $3 per dozen

1 answer:

max2010maxim [7]3 years ago

5 0

Answer:

All of your choices are correct.

Step-by-step explanation:

4.50 ÷ 18 = .25 each

.25 x 4 = 1.00

.25 x 36 = 9.00

12 x .25 = 3.00

You might be interested in

harry buys 22 fish he has a round fish bowl and a rectangular fish tank how could he place the fish in the bowl and tank

Lana71 [14]

Answer: put 11 in each one

Step-by-step explanation:

6 0

3 years ago

If 1/4 of the apples was given to zion and in total was 40 what fraction for the rest was oranges

Inessa05 [86]

Answer:

3/4 of the fruits were oranges.

Step-by-step explanation:

5 0

4 years ago

Read 2 more answers

In a poll, 74% of the people polled answered yes to the question "Are you in favor of the death penalty for a person convicted o

Maksim231197 [3]

Answer:

324

Step-by-step explanation:

given that in a poll, 74% of the people polled answered yes to the question "Are you in favor of the death penalty for a person convicted of murder?"

i.e. Sample proportion $p=0.74\\q =1-p =0.26\\$

Margin of error = 4% = 0.04

Confidence level =90%

Z critical value for 90% = 1.645

Margin of error = 1.645 * std error

Hence std error = $\frac{0.04}{1.645} \\=0.0243$

Std error is also equal to

$\sqrt{\frac{pq}{n} } =\sqrt{\frac{0.74(0.26)}{n} } =0.0243\\\sqrt{n} =18..05\\n = 325.83~324$

Sample size should be 324.

The formula is sample size = (Z critical value)^2 (pq)/(Margin of error )^2

3 0

4 years ago

The circumference of a sphere was measured to be 80 cm with a possible error of 0.5 cm. A) Use differentials to estimate the max

siniylev [52]

Answer:

A) The maximum error in the calculated surface area: $25cm^2$

Relative error: $0.013$

B) The maximum error in the calculated volume: $162cm^2$

Relative error: $0.019$

Step-by-step explanation:

A) The formula for the surface area is:

$A=4\pi r^2$

The measured value is the circumference which is equal to:

$C=2\pi r$

then the radius is:

$r=\frac{C}{2\pi}$

Substituting in the formula of the surface:

$A=4\pi(\frac{C}{2\pi})^2\\A=4\pi(\frac{C^2}{4\pi^2})\\A=\frac{C^2}{\pi}$

Using the formula to calculate the error:

$dy=f'(x)dx$

Where $x$ is the variable measured and $y$ is a function of $x$ ( $y=f(x)$ ).

$dA=f'(C)dC\\dA=\frac{2C^{(2-1)}}{\pi}dC\\dA=\frac{2C}{\pi}dC$

We have C=80cm and dC=0.5cm

$dA=\frac{2C}{\pi}dC\\dA=\frac{2(80)}{\pi}(0.5)\\dA=\frac{160}{\pi}(0.5)\\dA=50.9296(0.5)\\dA=25.4648\approx25cm^2$

The relative error is the maximum error divide by the total area. The total area is: $A=\frac{C^2}{\pi}=\frac{(80)^2}{\pi}=\frac{6400}{\pi}=2037.1833cm^2$

$\frac{dA}{A}=\frac{25.4648}{2037.1833} =0.0125\approx0.013$

B) The formula for the volume is:

$V=\frac{4}{3} \pi r^3$

Using $r=\frac{C}{2\pi}$

$V=\frac{4}{3} \pi r^3\\V=\frac{4}{3} \pi (\frac{C}{2\pi})^3\\V=\frac{4}{3} \pi (\frac{C^3}{8\pi^3})\\V=\frac{1}{3}(\frac{C^3}{2\pi^2})\\V=\frac{C^3}{6\pi^2}$

The maximum error is:

$dV=\frac{3C^{3-1}}{6\pi^2}dC\\dV=\frac{C^{2}}{2\pi^2}dC\\dV=\frac{(80)^{2}}{2\pi^2}(0.5)\\dV=\frac{6400}{2\pi^2}(0.5)\\dV=\frac{6400}{2\pi^2}(0.5)\\dV=(324.2278)(0.5)\\dV=162.1139\approx162cm^2$

The calculated volume is:

$V=\frac{C^3}{6\pi^2}\\V=\frac{(80)^3}{6\pi^2}\\V=\frac{512000}{6\pi^2}\\V=8646.0743$

The relative error is:

$\frac{dV}{V}=\frac{162.1139}{8646.0743}=0.0188\approx0.019$

3 0

3 years ago

Jillian surveyed students at her school and found out the following probabilities: P ( freshman ) = 0.30 P ( plays instrument )

VLD [36.1K]

Answer: 1/3

Step-by-step explanation:

6 0

3 years ago