Can someone help with these 3?

234.A 124/B 136.B 156.D

makvit [3.9K]

I think it’s D. 156 degrees

7 0

3 years ago

The three shapes below represent the bases of three different prisms. Each grid is 1 unit x 1 unit, and each prism has a height

8_murik_8 [283]

Then it’s 20 units I think

8 0

3 years ago

What is the probability of rolling a dice at most 3 times until a 6 occurs

IRISSAK [1]

Answer:

Probablity of getting six in at most three roll= 0.199.

Step-by-step explanation:

Given: Dice rolled at most 3 times untill a 6 occurs.

First, finding the probablity of getting 6 in a dice if rolled once.

Probablity= $\frac{chances\ of\ occurance}{Total\ number\ of\ event}$

We know, dice have six side, therefore, total number of event will be 6.

∴ Probablity of getting six in one roll= $\frac{1}{6}$

As given, Dice is rolled at most 3 times.

Now, finding the probablity of getting 6 in a dice if rolled 3 times.

∴ Probablity of getting six in three roll= $\frac{1}{6}+(\frac{1}{6})^{2} +(\frac{1}{6})^{3}$

⇒ Probablity of getting six in three roll= $\frac{1}{6}+\frac{1}{36} +\frac{1}{216}$

Taking LCD 216

⇒Probablity of getting six in three roll= $\frac{1\times 36+ 6\times 1+1}{216}$

⇒Probablity of getting six in three roll= $\frac{43}{216}$

∴Probablity of getting six in three roll=0.199

3 0

3 years ago

What is the probability that a random person who tests positive for a certain blood disease actually has the disease, if we know

xeze [42]

Answer:

Step-by-step explanation:

Hello!

Any medical test used to detect certain sicknesses have several probabilities associated with their results.

Positive (test is +) ⇒ P(+)

True positive (test is + and the patient is sick) ⇒ P(+ ∩ S)

False-positive (test is + but the patient is healthy) ⇒P(+ ∩ H)

Negative (test is -) ⇒ P(-)

True negative (test is - and the patient is healthy) ⇒ P(- ∩ H)

False-negative (test is - but the patient is sick) ⇒ P(- ∩ S)

The sensibility of the test is defined as the capacity of the test to detect the sickness in sick patients (true positive rate).

⇒ P(+/S) = P(+ ∩ S)

P(S)

The specificity of the test is the capacity of the test to have a negative result when the patients are truly healthy (true negative rate)

⇒ P(-/H) = P(- ∩ H)

P(H)

For this particular blood disease the following probabilities are known:

1% of the population has the disease: P(S)= 0.01

95% of those who are sick, test positive for it: P(+/S)= 0.95 (sensibility of the test)

2% of those who don't have the disease, test positive for it: P(+/H)= 0.02

The probability of a person having the blood sickness given that the test was positive is:

P(S/+)= P(+ ∩ S)

P(+)

The first step you need to calculate the intersection between both events + and S, for that you will use the information about the sickness prevalence in the population and the sensibility of the test:

P(+/S) = P(+ ∩ S)

P(S)

P(+/S)* P(S) = P(+ ∩ S)

P(+ ∩ S) = 0.95*0.01= 0.0095

The second step is to calculate the probability of the test being positive:

P(+)= P(+ ∩ S) + P(+ ∩ H)

Now we know that 1% of the population has the blood sickness, wich means that 99% of the population doesn't have it, symbolically: P(H)= 0.99

Then you can clear the value of P(+ ∩ H):

P(+/H) = P(+ ∩ H)

P(H)

P(+/H)*P(H) = P(+ ∩ H)

P(+ ∩ H) = 0.02*0.99= 0.0198

Next you can calculate P(+):

P(+)= P(+ ∩ S) + P(+ ∩ H)= 0.0095 + 0.0198= 0.0293

Now you can calculate the asked probability:

P(S/+)= P(+ ∩ S) = 0.0095 = 0.32

P(+) 0.0293

I hope it helps!

6 0

3 years ago

What is the directrix of the parabola defined by 1/4(y+3)=(x-2)^2

Charra [1.4K]

This is a parabola which opens upwards and the directrix will be of the form
y = k

the general form is

4p(y - k) = (x - h)^2 we have:-

1/4(y + 3) = (x - 2)^2

so the vertex is at (2, -3)

4p = 1/4 so p = 1/16

so the focus will be at (2 , -2 15/16)

and directrix is y = -3 1/16

4 0

3 years ago