Double a number and subtract nine. algebraic expression

Mathematics

1 answer:

insens350 [35]3 years ago

3 0

Answer:

2y - 9

Step-by-step explanation:

number = y

2 × y - 9

2 × y can be simplified to 2y.

2y - 9

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at a sale search were sold for $15 each. This price was 80% of the original price. What was the original price?

emmasim [6.3K]

Let's say the original price was "x", thus "x" is the 100%, and we know that 15 is 80% of that, thus

$\bf \begin{array}{ccll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
x&100\\
15&80
\end{array}\cfrac{x}{15}=\cfrac{100}{80}\implies x=\cfrac{1500}{80}$

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3 years ago

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A TV company when purchasing thousands electronic components apply this sampling plan: randomly select 15 of them and then accep

katrin [286]

<h2>Answer with explanation:</h2>

According to the Binomial probability distribution ,

Let x be the binomial variable .

Then the probability of getting success in x trials , is given by :

$P(X=x)=^nC_xp^x(1-p)^{n-x}$ , where n is the total number of trials or the sample size and p is the probability of getting success in each trial.

As per given , we have

n = 15

Let x be the number of defective components.

Probability of getting defective components = P = 0.03

The whole batch can be accepted if there are at most two defective components. .

The probability that the whole lot is accepted :

$P(X\leq 2)=P(x=0)+P(x=1)+P(x=2)\\\\=^{15}C_0(0.03)^0(0.97)^{15}+^{15}C_1(0.03)^1(0.97)^{14}+^{15}C_2(0.03)^2(0.97)^{13}\\\\=(0.97)^{15}+(15)(0.03)^1(0.97)^{14}+\dfrac{15!}{2!13!}(0.03)^2(0.97)^{13}\\\\\approx0.63325+0.29378+0.06360=0.99063$

∴The probability that the whole lot is accepted = 0.99063

For sample size n= 2500

Expected value : $\mu=np= (2500)(0.03)=75$

The expected value = 75

Standard deviation : $\sigma=\sqrt{np(1-p)}=\sqrt{2500(0.03)(0.97)}\approx8.53$

The standard deviation = 8.53

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3 years ago

Suppose A and B are independent events if P(A) = 0.4 And P(B) = 0.1, what is P(A'uB)? APEX

Aloiza [94]

For Independent Events, P(A) × P(B) = P(A∩B)

so we have, P(A∩B) = 0.4×0.1 = 0.04

P(A') = 1 - 0.4 = 0.6

This information can be represented on a Venn diagram as shown below

P(A'∪B) means the union of everything that is not A with everything that is B

P(A'∪B) = 0.06 + 0.54 + 0.04 = 0.64