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Bogdan [553]
2 years ago
13

Petra is shopping with 2 of her friends. She buys a note book and six identical pencils. The note book costs the same as 2 of th

e pencils. Her bill is £16.80. How much does a note book cost?
Mathematics
1 answer:
max2010maxim [7]2 years ago
3 0

Answer: £4.20

Each 2 of pencils is £4.20 multiply that by 3 your get 12.60, the notebook is the same price of 2 pencils so that must mean it is £4.20

4.20 x 4 = 16.80

3 £4.2 from the 6 pencils

and 1 £4.2 from the notebook

Hope this helps!

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A plane ticket barcelona costs £175 the price decreases by 6% work out the new price
Bond [772]

Answer: £164.50

175 decreased by 6% = 164.5

Absolute change (actual difference):

164.5 - 175 = - 10.5

Step-by-step explanation:

175 - Percentage decrease =

175 - (6% × 175) =

175 - 6% × 175 =

(1 - 6%) × 175 =

(100% - 6%) × 175 =

94% × 175 =

94 ÷ 100 × 175 =

94 × 175 ÷ 100 =

16,450 ÷ 100 =

164.5

£164.50

6 0
1 year ago
Read 2 more answers
Let x stand for the length of an individual screw. 100 screws were sampled at a time. The population mean is 2.5 inches and the
goldfiish [28.3K]

Answer:

The mean is defining the average length(2.5in) of the 100 measured screws.

Step-by-step explanation:

The mean is usually calculated in order to determine the average of a set of values.

8 0
1 year ago
The height of a grain of a cylindrical silo is is increasing at a constant rate of 4 feet per minute At what rate is the volume
Dafna11 [192]
The answer is 2 min and 30 sec
7 0
1 year ago
A study was recently conducted at a major university to estimate the difference in the proportion of business school graduates w
sveta [45]

Answer:

(0.1875-0.274) - 1.96 \sqrt{\frac{0.1875(1-0.1875)}{400} +\frac{0.274(1-0.274)}{500}}=-0.1412  

(0.1875-0.274) + 1.96 \sqrt{\frac{0.1875(1-0.1875)}{400} +\frac{0.274(1-0.274)}{500}}=-0.0318  

And the 95% confidence interval would be given (-0.1412;-0.0318).  

We are confident at 95% that the difference between the two proportions is between -0.1412 \leq p_A -p_B \leq -0.0318

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".  

The margin of error is the range of values below and above the sample statistic in a confidence interval.  

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".  

p_A represent the real population proportion for business  

\hat p_A =\frac{75}{400}=0.1875 represent the estimated proportion for Business

n_A=400 is the sample size required for Business

p_B represent the real population proportion for non Business

\hat p_B =\frac{137}{500}=0.274 represent the estimated proportion for non Business

n_B=500 is the sample size required for non Business

z represent the critical value for the margin of error  

The population proportion have the following distribution  

p \sim N(p,\sqrt{\frac{p(1-p)}{n}})  

Solution to the problem

The confidence interval for the difference of two proportions would be given by this formula  

(\hat p_A -\hat p_B) \pm z_{\alpha/2} \sqrt{\frac{\hat p_A(1-\hat p_A)}{n_A} +\frac{\hat p_B (1-\hat p_B)}{n_B}}  

For the 95% confidence interval the value of \alpha=1-0.95=0.05 and \alpha/2=0.025, with that value we can find the quantile required for the interval in the normal standard distribution.  

z_{\alpha/2}=1.96  

And replacing into the confidence interval formula we got:  

(0.1875-0.274) - 1.96 \sqrt{\frac{0.1875(1-0.1875)}{400} +\frac{0.274(1-0.274)}{500}}=-0.1412  

(0.1875-0.274) + 1.96 \sqrt{\frac{0.1875(1-0.1875)}{400} +\frac{0.274(1-0.274)}{500}}=-0.0318  

And the 95% confidence interval would be given (-0.1412;-0.0318).  

We are confident at 95% that the difference between the two proportions is between -0.1412 \leq p_A -p_B \leq -0.0318

7 0
1 year ago
Simplify the square root of four over the cubed root of four. four raised to the five sixths power four raised to the one sixth
romanna [79]

Answer:

(B)4^{1/6}

Four raised to the one-sixth power

Step-by-step explanation:

We want to simplify:  \dfrac{\sqrt{4} }{\sqrt[3]{4} }

First, we apply the fractional law of indices to each term.

\text{If  } a^{1/x}=\sqrt[x]{a},$ then:\\\sqrt{4}=4^{1/2}\\\sqrt[3]{4}=4^{1/3}

We then have:

\dfrac{\sqrt{4} }{\sqrt[3]{4} }=\dfrac{4^{1/2} }{4^{1/3} }\\$Applying the division law of indices: \dfrac{a^m }{a^n }=a^{m-n}\\\dfrac{4^{1/2} }{4^{1/3} }=4^{1/2-1/3}\\\\=4^{1/6}

The correct option is B.

7 0
1 year ago
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