Anyone know the answer to these?

Mathematics

1 answer:

Arturiano [62]3 years ago

8 0

Step-by-step explanation:

Speakers =£ 31.5

Headphones =£ 4.8

Book =£ 3.85

Mobile phone =£ 36

mouse = £12.75

DVD =£ 10.2

Hope it will help you :)

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I need help with both of them please!( Sample questions 13 and 14)

zaharov [31]

$First~exercise! \\ We~ have `there ~some~ triangles.(2) \\ 1)~In~ a ~triangle~,the~degree~of~all~angles~is~180! \\ We~have~2~angles~known,so: \\ 180=x+45+56 \\ 180=101+x \\ x=79 \\ \\ Second~triangle! \\ We~have~to~find~2~angles! \\ An ~elongated`~angle~have~180~degrees! \\ 180=79+50+y \\ y=51. \\ In~the~second~triangle~,we~have~to~find~the`third~angle. \\ We~have~a~right~angle,so--\ \textgreater \ 90~degrees! \\ 180=90+51+z \\ z=39! \\ We~found~all~the~angles!(We~are`happy~now!!!~:))) \\ Second~exercise! \\ With~the~Pythagoras' Theorem,we~can~find~the~diagonal~in~this~ \\ rectangle! \\ c ^{2} =10 ^{2} +14 ^{2} \\ c ^{2} =100+196 \\ c= \sqrt{296} \\ c=17,20...$

8 0

3 years ago

"a pollster wishes to estimate the number of left-handed scientists. how large of a sample is needed in order to be 98% confiden

nadezda [96]

The sample size should be 250.

Our margin of error is 4%, or 0.04. We use the formula

$\text{ME}=z\sqrt{\frac{\hat{p}(1-\hat{p})}{n}}$

To find the z-score:
Convert 98% to a decimal: 0.98
Subtract from 1: 1-0.98 = 0.02
Divide both sides by 2: 0.02/2 = 0.01
Subtract from 1: 1-0.01 = 0.99

Using a z-table (http://www.z-table.com) we see that this value has a z-score of approximately 2.33. Using this, our margin of error and our proportion, we have:

$0.04=2.33\sqrt{\frac{0.08(1-0.08)}{n}}
\\
\\0.04=2.33\sqrt{\frac{0.08(0.92)}{n}}$

Divide both sides by 2.33:
$\frac{0.04}{2.33}=\sqrt{\frac{0.08(0.92)}{n}}$

Square both sides:
$(\frac{0.04}{2.33})^2=\frac{0.08(0.92)}{n}$

Multiply both sides by n:
$(\frac{0.04}{2.33})^2n=0.08(0.92)$

Divide both sides to isolate n:
$\frac{0.08(0.92)}{(\frac{0.04}{2.33})^2}=n
\\
\\249.73=n
\\n\approx 250$

4 0

3 years ago

Help me this is hard

siniylev [52]

Following PEMDAS is crucial to solving these. Please Excuse My Dear Aunt Sally

P - Parenthesis

E - Exponents

M - Multiplication

D - Division

A - Addition

S - Subtraction

Multiplication/Division and Addition/Subtraction are interchangeable.

Now then, number 1 has the following:

$4-2*409-8*96$

There are no parenthesis or exponents, but there is multiplication, so we will start with multiplying. There are two multiplication expressions in the problem.

$-2 * 409 = -818$