It says the set (1,2,3) can help?

No es el 3 pero si es el numero 7

7 0

3 years ago

The Cobb family of Fremont is looking at ways to decrease their home water and energy usage. Their current electric hot-water he

OverLord2011 [107]

Answer:

ai) 73000 gal/yr

aii) $730 per year

b) 1000 days

Step-by-step explanation:

ai) The water usage per day is ...

(4 showers/day)(10 min/shower)(5 gal/min) = 200 gal/day

Then the usage per year is ...

(200 gal/day)(365 days/yr) = 73,000 gal/yr

__

aii) The cost of electricity is the cost of heating half the water usage, so is ...

(0.20 kWh/gal)(1/2)(73,000 gal/yr)($0.10/kWh) = $730/yr

__

b) The current daily cost of electricity for heating water is ...

($730/yr)/(365 days/yr) = $2/day

If the cost is cut in half, it will be $1 per day. That means the savings is $1 per day, so it will take 1000 days to recover the $1000 initial cost. (Effectively, the average cost for the first 1000 days is the same as if the water heater had not been replaced.)

5 0

4 years ago

Find the x and y intercepts of the equation. Express your answers as points. 5 x + 7 y = − 140

iVinArrow [24]

Answer:

x-intercept(s): (-28, 0)

y-intercept(s): (0, -20)

Step-by-step explanation:

Try This Answer.

5 0

3 years ago

SAT scores have a mean of 1026 and a standard deviation of 209. ACT scores have a mean of 20.8 and a standard deviation of 4.8.

Y_Kistochka [10]

Answer:

The z-score for SAT exam of junior is much small than his ACT score. This means he performed well in his ACT exam and performed poor in his SAT exam.

Step-by-step explanation:

Mean SAT scores = 1026

Standard Deviation = 209

Mean ACT score = 20.8

Standard Deviation = 4.8

We are given SAT and ACT scores of a student and we have to compare them. We cannot compare them directly so we have to Normalize them i.e. convert them into such a form that we can compare the numbers in a meaningful manner. The best way out is to convert both the values into their equivalent z-scores and then do the comparison. Comparison of equivalent z-scores will tell us which score is higher and which is lower.

The formula to calculate the z-score is:

$z=\frac{x-\mu}{\sigma}$

Here, μ is the mean and σ is the standard deviation. x is the value we want to convert to z score.

z-score for junior scoring 860 in SAT exam will be:

$z=\frac{860-1026}{209}=-7.59$

z-score for junior scoring 16 in ACT exam will be:

$z=\frac{16-20.8}{4.8}=-1$

The z-score for SAT exam of junior is much small than his ACT score. This means he performed well in his ACT exam and performed poor in his SAT exam.

4 0

3 years ago

Given a = -3 and b= 4 and c=-5, evaluate atb C -1/5 O 1/5 0 -7/5

stiv31 [10]

Answer:

I got - 5 as an answer.

I don't think I made a mistake.

Please if you find any error, contact me in the comment section.

Step-by-step explanation:

$a = -3 , b= 4 ,c= - 5\\(a+b)c\\(-3+4)-5\\(1)*(-5)\\Answer = -5$

8 0

3 years ago