Answer:
The probability is 0.9211
Step-by-step explanation:
Let's call K the event that the student know the answer, G the event that the student guess the answer and C the event that the answer is correct.
So, the probability P(K/C) that a student knows the answer to a question, given that she answered it correctly is:
P(K/C)=P(K∩C)/P(C)
Where P(C) = P(K∩C) + P(G∩C)
Then, the probability P(K∩C) that the student know the answer and it is correct is:
P(K∩C) = 0.7
On the other hand, the probability P(G∩C) that the student guess the answer and it is correct is:
P(G∩C) = 0.3*0.2 = 0.06
Because, 0.3 is the probability that the student guess the answer and 0.2 is the probability that the answer is correct given that the student guess the answer.
Therefore, The probability P(C) that the answer is correct is:
P(C) = 0.7 + 0.06 = 0.76
Finally, P(K/C) is:
P(K/C) = 0.7/0.76 = 0.9211
Answer:
2x = 40°
3x = 60°
4x = 80°
Step-by-step explanation:
2x+3x+4x = 180°
9x = 180
x = 20
SO
2x = 2(20) = 40°
3x = 3(20) = 60°
4x = 4(20) = 80°
Cos 75 = 45 + 30
Formula: cos 45 x cos 30 - sin 45 x sin 30
Cos 45 = root 2 / 2
Cos 30 = root 3 / 2
Sin 45 = root 2 / 2
Sin 30 = 1 / 2
Answer:
300
Step-by-step explanation:
it is rounded to 300 because the number 342 is closer to 300 than it is to 400 if its 350 and up then it would be rounded to 400 but its not so its rounded to 300
