Is her hair really that long... Possibly a brainly help me understand scientific notation better <3

You are trying to estimate the average amount a family spends on food during a year. In the past the standard deviation of the a

svetoff [14.1K]

Answer:

$n=(\frac{2.58(1000)}{50})^2 =2662.56 \approx 2663$

So the answer for this case would be n=2663 rounded up to the nearest integer

Step-by-step explanation:

We have the following info:

$ME = 50$ margin of error desired

$\sigma = 1000$ the standard deviation for this case

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

And on this case we have that ME =50 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

The critical value for 99% of confidence interval now can be founded using the normal distribution. The significance is $\alpha=0.01$ . And for this case would be $z_{\alpha/2}=2.58$ , replacing into formula (b) we got:

$n=(\frac{2.58(1000)}{50})^2 =2662.56 \approx 2663$

So the answer for this case would be n=2663 rounded up to the nearest integer

5 0

2 years ago

We are interested in the dimensions of a certain rectangle. this rectangle has length twice the side of the square and width thr

Mila [183]

Area of square = s^2
Area of Rectangle = lw
l = 2s

w+3 = s
solve for w, w=s-3
Now we have l and w.
Plug both into area of rectangle formula so: (2s)(s-3)
Since both areas are equal set both equations equal to each other:
(2s)(s-3)=s^2
Now simplify
2s^2-6s=s^2
s^2-6s=0, Solve for s.
Factor polynomial. s(s-6)=0 , s can be equal to 0 or 6. HOWEVER, you cannot have a side length of 0 therefore the side length has to be 6.
Now plug in s for the length formula for the rectangle:
l = 2s so... l = 2(6) so length of rectangle = 12.
Now plug in s for the width formula for the rectangle:
w+3=s so... w+3=6 so width of rectangle = 3.
Now the dimensions of the rectangle are 12 by 3. 12 being length and 3 width.
To CHECK:
Find area of rectangle:
A=lw so A=3 times 12 so A=36
Find area of square:
We know the side is equal to 6 so
A=s^2 so 6^2 = 36
The areas are equal that verifies the answer of 12 by 3.

8 0

2 years ago

At Greenwood Landscaping, rock costs $47.50 per ton. How much would 2.5 tons cost?

Grace [21]

Answer:

Hey!

Your answer is $118.75!

Step-by-step explanation: How did I get this?

STEP 1: So we know that for a ton of rock costs us $47.50...

To get 2 tons all we have to do is to MULTIPLY $47.50 by 2...

(47.50 x 2 = 95)

STEP 2: So for $95, you will get 2 tons of rock!

Now to get the .5 tons of rock in price form, we have to get the price of the whole 2.5 tons and DIVIDE BY 2

(47.50 ÷ 2 = 23.75)

STEP 3: So now we have the costs for 2 tons and the price for HALF a ton.

What we do now is easy...we ADD THE VALUES TOGTHER!

(95 + 23.75 = $118.75)

The result of $118.75 after adding them together is the PRICE OF 2 TONS!

I HOPE THIS HELPED YOU!

4 0

2 years ago

write the slope intercept form of the equation of each line given the slope and y intercept. // slope= 1/3 y-intercept= 4 // slo

professor190 [17]

Answer:

Slope: 1/3; Y-iintercept: 4 y=1/3x+4

Slope: -2; Y-intercept: 4 y=-2x

Step-by-step explanation:

Hope this helps :3

if it did pls mark brainliest

6 0

2 years ago

victor needs 300 feet of rope.The rope he wants to buy is sold by yards.He knows that there are 3 feet in 1 yard.How many yards

barxatty [35]

We need to convert 300 feet to yards.

We know,

3 feet = 1 yard

Hence,

300 feet * 1 yard/3 feet = 300/3 = 100 yards

He should buy 100 yards

5 0

1 year ago