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3 years ago

7

Jane bought an item for $40 that, after seeing it had a 20% discount. janes friend said the original price was $48. is she right

or wrong?

1 answer:

ale4655 [162]3 years ago

6 0

Jane's friend is wrong, the original price would be $200

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Which number line best represents the solution to the inequality 3.3w - 9 > -22.2?<br> picture ↓

Sergeu [11.5K]

Answer:

solve the inequality in the form of w

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3 years ago

A random sample of 10 parking meters in a beach community showed the following incomes for a day. Assume the incomes are normall

Vlad1618 [11]

Answer: (2.54,6.86)

Step-by-step explanation:

Given : A random sample of 10 parking meters in a beach community showed the following incomes for a day.

We assume the incomes are normally distributed.

Mean income : $\mu=\dfrac{\sum^{10}_{i=1}x_i}{n}=\dfrac{47}{10}=4.7$

Standard deviation : $\sigma=\sqrt{\dfrac{\sum^{10}_{i=1}{(x_i-\mu)^2}}{n}}$

$=\sqrt{\dfrac{(1.1)^2+(0.2)^2+(1.9)^2+(1.6)^2+(2.1)^2+(0.5)^2+(2.05)^2+(0.45)^2+(3.3)^2+(1.7)^2}{10}}$

$=\dfrac{30.265}{10}=3.0265$

The confidence interval for the population mean (for sample size <30) is given by :-

$\mu\ \pm t_{n-1, \alpha/2}\times\dfrac{\sigma}{\sqrt{n}}$

Given significance level : $\alpha=1-0.95=0.05$

Critical value : $t_{n-1,\alpha/2}=t_{9,0.025}=2.262$

We assume that the population is normally distributed.

Now, the 95% confidence interval for the true mean will be :-

$4.7\ \pm\ 2.262\times\dfrac{3.0265}{\sqrt{10}} \\\\\approx4.7\pm2.16=(4.7-2.16\ ,\ 4.7+2.16)=(2.54,\ 6.86)$

Hence, 95% confidence interval for the true mean= (2.54,6.86)

7 0

3 years ago

Please help. Question 22 Graph the following equation:

jeka57 [31]

I hope this helps you

7 0

3 years ago

(a) The position of a particle at time t is s(t) = t^3 + t. Compute the average velocity over the time interval [7, 12].(b) Esti

ryzh [129]

Answer:

<h2>a) Average velocity = 278 units</h2><h2>b) Instantaneous velocity at t = 7 seconds is 148 units</h2>

Step-by-step explanation:

a) Average velocity is the ratio of displacement to time.

We have

s(t) = t³ + t

t is in between 7 and 12

s(7) = 7³ + 7 = 350

s(12) = 12³ + 12 = 1740

Displacement = 1740 - 350 = 1390

Time = 12 - 7 = 5

Displacement = Average velocity x time

1390 = Average velocity x 5

Average velocity = 278 units

b) s(t) = t³ + t

Differentiating

v(t) = 3t² + 1

At t = 7

v(t) = 3 x 7² + 1 = 148 units

Instantaneous velocity at t = 7 seconds is 148 units

8 0

3 years ago

Fine the area of a circle with a radius of 7 in. Write the formula, substitute, solve.

bija089 [108]

Formula: A=(pi)r^2

Substitution: A=3.14(7^2)

A=3.14(49)

Solve: A=153.86 in^2

*I personally like to use the pi sign on my calculator to multiply the radius squared by, but my keyboard did not have a pi sign. Usually, the pi sign is more exact. If you used the pi sign, your answer would be 153.94 inches^2. Hope this helps!

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3 years ago