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3 years ago

10 POINTS PLEASE SOS IK TIMED

Mathematics

1 answer:

Korvikt [17]3 years ago

6 0

I honestly went by elimination so

Work:

Teacher = 4 Student = 2

A) 5 Teachers = 20 pizza 1 Student = 2 = 22

B) 4 Teachers= 16 Pizza 2 Student = 4 = 20

C) 3 Teachers = 12 Pizza 3 Student = 6 = 18

D) 2 Teachers = 8 Pizza 4 Student = 8 = 16

E) 1 Teacher = 4 Pizza 5 Student= 10 = 14

Answer

There are exactly 3 Teachers and 3 Students. (Answer C)

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Find the length of AC Use that length to find the length of

Gekata [30.6K]

Answer:

1. AC = 5 cm

2. CD = 10.7 cm

Step-by-step explanation:

Looking at the left triangle, we see that AC is the side "opposite" of the angle given and AB is the "hypotenuse".

Which trigonometric ratio relates "opposite" to "hypotenuse"?

Yes, that's SINE.

So we can write:

$Sin(30)=\frac{AC}{10}\\AC=10*Sin(30)$

We know from 30-60-90 triangle, Sin(30) = 0.5, so we have:

$AC=10*Sin(30)\\AC=10*0.5\\AC=5$

Thus,

AC = 5 cm

Now, looking at right side triangle, we know AC, side "opposite" and we want to find CD, side "adjacent". Which trig ratio relates these 2 sides?

Yes, that's tan!

Thus we can write:

$Tan(25)=\frac{5}{CD}\\CD=\frac{5}{Tan(25)}$

Now using calculator, we get our answer to be:

CD = $\frac{5}{Tan(25)}=10.7$

CD = 10.7 cm

8 0

3 years ago

You have a coin collection of nickels and dimes containing 63 coins. If you have

xxTIMURxx [149]

Answer: 25 nickels

Step-by-step explanation:

EQUATIONS:

quantity: n + d = 63

value: 5n + 10d = 505

-------------------------

Divide thru the 2nd equation by 5 to get:

n + 2d = 101

----------------

Subtract that from the 1st equation:

-d = -38

d = 38 (# of dimes)

---------------

Substitute that into n+d=63 to solve for "n":

n + 38 = 63

n = 25 (# of nickels)

6 0

3 years ago

A bank is trying to determine which model of safe to install. The bank manager believes that each model is equally resistant to

alexandr402 [8]

Answer:

So on this case the 95% confidence interval would be given by (-1.152;5.152).

$-1.152 < \mu_{safe1}-\mu_{safe2}$

Should we conclude that the average time it takes experts to crack the safes does not differ by model at the 5% significance level?

A) Yes, the 95% confidence interval for ?D contains 0.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Solution

Let put some notation

x=value for Safe 1 , y = value for Safe 2

x: 103, 90, 64, 120, 104, 92, 145, 106, 76

y: 101, 94, 58, 112, 103, 90, 140, 110, 74

The first step is calculate the difference $d_i=x_i-y_i$ and we obtain this:

d: 2, -4, 6, 8, 1, 2, 5, -4, 2

The second step is calculate the mean difference

$\bar d= \frac{\sum_{i=1}^n d_i}{n}= \frac{18}{9}=2$

The third step would be calculate the standard deviation for the differences, and we got:

$s_d =\frac{\sum_{i=1}^n (d_i -\bar d)^2}{n-1} =4.093$

The next step is calculate the degrees of freedom given by:

$df=n-1=9-1=8$

Now we need to calculate the critical value on the t distribution with 8 degrees of freedom. The value of $\alpha=1-0.95=0.05$ and $\alpha/2=0.025$ , so we need a quantile that accumulates on each tail of the t distribution 0.025 of the area.