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2 years ago

Help me kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk

Mathematics

1 answer:

Natalija [7]2 years ago

5 0

Answer:

this is not mathmatics

Step-by-step explanation:

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Answer:A for the first one and C for the second one

Step-by-step explanation:

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3 years ago

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Solve the following equation 7 • 10^n = 7000

marysya [2.9K]

Answer:

N=3

Step-by-step explanation:

7.10^n =7000

10^n =1000

10^n = 10^3

(coz bases are the same powers are equal)

Therefore n =3

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2 years ago

Brenda went to the store 30 times last

Artist 52 [7]

Answer:

7.5

Step-by-step explanation:

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3 years ago

Cable Strength: A group of engineers developed a new design for a steel cable. They need to estimate the amount of weight the ca

KatRina [158]

Answer:

95% confidence interval for the mean breaking strength of the new steel cable is [763.65 lb , 772.75 lb].

Step-by-step explanation:

We are given that the engineers take a random sample of 45 cables and apply weights to each of them until they break. The mean breaking weight for the 45 cables is 768.2 lb. The standard deviation of the breaking weight for the sample is 15.1 lb.

Since, in the question it is not specified that how much confidence interval has be constructed; so we assume to be constructing of 95% confidence interval.

Firstly, the Pivotal quantity for 95% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean breaking weight = 768.2 lb

s = sample standard deviation = 15.1 lb

n = sample of cables = 45

$\mu$ = population mean breaking strength

Here for constructing 95% confidence interval we have used One-sample t test statistics as we don't know about population standard deviation.

So, 95% confidence interval for the population mean, $\mu$ is ;

P(-2.02 < $t_4_4$ < 2.02) = 0.95 {As the critical value of t at 44 degree

of freedom are -2.02 & 2.02 with P = 2.5%}

P(-2.02 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 2.02) = 0.95

P( $-2.02 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $2.02 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

P( $\bar X-2.02 \times {\frac{s}{\sqrt{n} } }$ < $\mu$ < $\bar X+2.02 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

95% confidence interval for $\mu$ = [ $\bar X-2.02 \times {\frac{s}{\sqrt{n} } }$ , $\bar X+2.02 \times {\frac{s}{\sqrt{n} } }$ ]

= [ $768.2-2.02 \times {\frac{15.1}{\sqrt{45} } }$ , $768.2+2.02 \times {\frac{15.1}{\sqrt{45} } }$ ]

= [763.65 lb , 772.75 lb]

Therefore, 95% confidence interval for the mean breaking strength of the new steel cable is [763.65 lb , 772.75 lb].

3 0

3 years ago

PLEASE PLEASE PLEASE HELP ME ANSWER THIS QUESTION QUICK!! The picture of the question is down below.

antiseptic1488 [7]

Answer:

Step-by-step explanation:

You must multiply the first two equation which is 5x+1 and x this will give you

5x^2 + x. The bold goes in the first box.

Then do the same thing for 2x+1 and x+1 which will give you 2x^2+2x+x+1 or 2x^2+3x+1. This goes in the second box.

In the last box you will add 5x^2 +x and 2x^2 +3x +1, which gives you 7x^2 +4x +1.

Goes in the last box.

Hope this helps you.

7 0

2 years ago