Ask question

Ask question

All categories

elena-14-01-66 [18.8K]

2 years ago

8

PLEASE ANYONE HELP I NEED IT DONE BY 11:59 this is the second part to the first part six question all together someone please he

lp

1 answer:

Archy [21]2 years ago

6 0

I believe question 4 is 40 but I’m not sure

You might be interested in

Carl deposited $5,142 into a savings account 20 years ago. The account has an interest rate of 3.8% and the balance is currently

Aleksandr [31]

Here is the formula you'll need
Total = Principal * (1 + (rate/n))^n*years
I don't know how to solve that for "n" so we'll use trial and error.

If compounded annually, total = <span> <span> <span> 10,841.24 </span> </span> </span>
If compounded quarterly, total = <span> <span> <span> 10,955.64 </span>
</span></span><span>If compounded monthly, total = </span> <span> <span> <span> 10,981.82 </span> </span> </span>
If compounded daily, total = <span> <span> <span> 10,994.58 </span> </span> </span>
Therefore the answer is "A", daily.

Source:
http://www.1728.org/compint3.htm

<span> </span><span><span> </span> </span>

3 0

3 years ago

An instructor in a college class recently gave an exam that was worth a total of 100 points. The instructor inadvertently made t

solniwko [45]

Answer:

B) Method 2 will increase the standard deviation of the students' scores.

Step-by-step explanation:

Given that an instructor in a college class recently gave an exam that was worth a total of 100 points.

The average score for his students was 43 and the standard deviation of the scores was 5 points.

And now he is considering two different strategies for rescaling the exam results of which:

Method 1 = Add 17 points to everyone's score.

Method 2 = Multiply everyone's score by 1.7 .

And we have to check what will be the impact of these methods on the standard deviation of the students' scores.

For this let us consider a simple example to understand this:

Firstly, Formula for calculating Standard Deviation = $\sqrt{\frac{\sum (X-Xbar)^{2}}{n-1}}$

Suppose,

X X - Xbar $(X - Xbar)^{2}$

3 3 - 6 = -3 -3 * -3 = 9

5 5 - 6 = -1 -1 * -1 = 1

10 10 - 6 = 4 4 * 4 = 16

<em>Mean of above data, Xbar</em> = $\frac{3+ 5+10}{3}$ = 6

<em>Standard Deviation of data </em>= $\sqrt{\frac{26}{3-1} }$ = 3.6055

Now let us suppose that we multiply each value of above data with 2 so the new data will be:

X X - Xbar $(X - Xbar)^{2}$

3*2 = 6 6 - 12 = -6 -6 * -6 = 36

5*2 = 10 10 - 12 = -2 -2 * -2 = 4

10*2 =20 20 - 12 = 8 8 * 8 = 64

<em>Mean of new data, Xbar </em>= $\frac{6+ 10+20}{3}$ = 12

<em>Standard Deviation of new data</em> = $\sqrt{\frac{104}{3-1} }$ = 7.2111

<em>Hence, we see that when we multiply any value to the data the standard deviation will increase and in other words it will multiplied by that value which value we multiplied with each data value i.e. when we multiply each data value with 2 the standard deviation also get multiplied by as </em>

3.6055 * 2 = 7.2111

Therefore option B is correct that Method 2 will increase the standard deviation of the students' scores.

<em>And on the other hand Similarly by adding any constant to the data the Standard Deviation will remain same. Therefore Method 1 will have no impact on standard deviation of the students' scores.</em>

8 0

3 years ago

Solve for x. 3/5 x=9 What should we do first? Finish solving it and what do you get for x? A) 27/5 B) 30 c) 15

kumpel [21]

Answer:

c.) 15

Step-by-step explanation:

1st Multiply both sides by 5: 5×3/5x=9×5

2nd Simplify: 3x=45

3rd Divide both sides by 3: 3x÷3=45÷3

4th Simplify: x=15

3 0

3 years ago

A radio telescope has a parabolic surface, as shown below.

krek1111 [17]

OK, so the graph is a parabola, with points x=0,y=0; x=6,y=-9; and x=12,y=0

Because the roots of the equation are 0 and 12, we know the formula is therefore of the form

y = ax(x - 12), for some a

So put in x = 6

-9 = 6a(-6)

9 = 36a

a = 1/4

So the parabola has a curve y = x(x-12) / 4, which can also be written y = 0.25x² - 3x

The gradient of this is dy/dx = 0.5x - 3

The key property of a parabolic dish is that it focuses radio waves travelling parallel to the y axis to a single point. So we should arrive at the same focal point no matter what point we chose to look at. So we can pick any point we like - e.g. the point x = 4, y = -8

Gradient of the parabolic mirror at x = 4 is -1

So the gradient of the normal to the mirror at x = 4 is therefore 1.

Radio waves initially travelling vertically downwards are reflected about the normal - which has a gradient of 1, so they're reflected so that they are travelling horizontally. So they arrive parallel to the y axis, and leave parallel to the x axis.

So the focal point is at y = -8, i.e. 1 metre above the back of the dish.

5 0

2 years ago

I need to know how to answer number 10

Ipatiy [6.2K]

Check the picture below.

3 0

3 years ago