What is the circumference of a circle with a radius of 8 in.? Use 3.14 for t.

Solve the System using elimination. <br><br> 5x-2y=15<br> 7x+7y=-28

steposvetlana [31]

Answer:

x=1 y=-5

Step-by-step explanation:

7(5x-2y=15) ---> 35x-14y=105

2(7x+7y=-28) --> + <u>14x+14y=-56</u>

49x=49 --->x=1

5(1)-2y=15 ---> 5-2y=15 ---> -2y=10 ---> y=-5

8 0

2 years ago

According to an almanac, 60% of adult smokers started smoking before turning 18 years old. (a) compute the mean and standard

larisa [96]

The given problem describes a binomial distribution with p = 60% = 0.6. Given that there are 400 trials, i.e. n = 400.

a.) The mean is given by:

$\mu=np=400\times0.6=240$

The standard deviation is given by:

$\sigma=\sqrt{npq} \\ \\ =\sqrt{np(1-p)} \\ \\ =\sqrt{400(0.6)(0.4)} \\ \\ =\sqrt{96}=9.80$

b.) The mean means that in an experiment of 400 adult smokers, we expect on the average to get about 240 smokers who started smoking before turning 18 years.

c.) It would be unusual to observe <span>340 smokers who started smoking before turning 18 years old in a random sample of 400 adult smokers because 340 is far greater than the mean of the distribution.
340 is greater than 3 standard deviations from the mean of the distribution.</span>

5 0

2 years ago

What is the equation of the line described below written in slope-iWhat is the equation of the line described below written in s

horsena [70]

The equation of a line passing through point (4, -1) and perpendicular to the line whose equation is 2x - y - 7 = 0 is y = -1/2x + 1

<h3>Equation of a line</h3>

A line is the shortest distance between two points. The equation of a line in point-slope form and perpendicular to a line is given as;

y - y1 = -1/m(x-x1)

where

m is the slope

(x1, y1) is the intercept

Given the following

Point = (4, -1)

Line: 2x-y - 7 = 0

Determine the slope

-y = -2x + 7

y= 2x - 7

Slope = 2

Substitute

y+1 = -1/2(x -4)

Write in slope-intercept form

2(y + 1) = -(x - 4)

2y+2 = -x + 4

2y = -x + 2

y = -1/2 + 1

Hence the equation of a line passing through point (4, -1) and perpendicular to the line whose equation is 2x - y - 7 = 0 is y = -1/2x + 1

Learn more on equation of a line here: brainly.com/question/13763238

#SPJ1

4 0

2 years ago

The heat developed in an electric wire varies jointly as the wires resistance, the time the current flows, & the square of t

never [62]

Answer:

4 ohms

Step-by-step explanation:

The question is "In two minutes a current of 5 amps develops 1,200 heat units in a wire of 8 ohms resistance. What resistance does a similar wire have, which develops 6,000 heat units with a current of 10 amps in 5 minutes?"

Current, I₁ = 5 A

Heat, Q₁ = 1200 units

Resistance, R₁ = 8 ohms

Time, t₁ = 2 min = 120 s

New heat, Q₂ = 6000 units

Current, I₂ = 10 A

New time, t₂ = 5 min = 300 s

We need to find the new resistance.

Heat developed is given by :

$Q=I^2Rt$

$\dfrac{Q_1}{I_1^2R_1t_1}=\dfrac{Q_2}{I_2^2R_2t_2}\\\\R_2=\dfrac{Q_2\times I_1^2R_1t_1}{Q_1I_2^2t_2}\\\\R_2=\dfrac{6000\times 5^2\times 8\times 120}{1200\times 10^2\times 300}\\\\=4\ \Omega$

So, the new resistance is 4 ohms.

5 0

2 years ago

Hillary earns $60 per week at her job, plus $2 for each item she sells. She wants to

AnnZ [28]

Answer:

60+2x≥300

Step-by-step explanation:

So we know that she makes a base of $60 a week and gets $2 extra for every item she sells. First, we set up an equation for how many items she would have to sell to make exactly $300 in a week. 60+2x=300. Now, all we do is replace the equal sign with a ≥ sign because it says at least which means more than or equal to.

8 0

2 years ago

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What is the circumference of a circle with a radius of 8 in.? Use 3.14 for t.​

What is the circumference of a circle with a radius of 8 in.? Use 3.14 for t.