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:
period = 2
Step-by-step explanation:
The period is the measure of 1 complete cycle of the wave
The wave enters at x = 0 , y = - 0.5
After 1 cycle the wave is at x = 2, y = - 0.5
period = 2 - 0 = 2
Answer: -5/3
Step-by-step explanation:
Use the slope formula: 
You substitute the numbers in and subtract to get -5/3.
Answer:
5/12
Step-by-step explanation:
X^2-X-6=(X-3)(X+2)
(X+2)/(x+2)=1
Which just leaves (x-3)
X=3
