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:
1- A
2- C
3- B
4- D
Step-by-step explanation:
The answer is 6,072,825,688
20 times 10 is 200 divided by 2 is 100. so 100 cm squared
Answer:
Step-by-step explanation:
x + y = 40
x>y
(11/2)y - (13/4)*x = - 25
x = 40 - y
(11/2)y - (13/4)(40-y) = - 25 multiply by 4
22y - 13( 40 - y) = - 100
22y - 520 + 13y = -400 Add 520
35y = 120
y = 120 / 35
y = 3 3/7
x = 40 - y
x = 36 4/7
