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
Let the number be n.
Then 3n+5 = n+40
Combining like terms, we get
2n = 35, and so n = 35/7, or 17 1/2.
Step-by-step explanation:
the product of −1 and −3
(-1)×(-3)
= 3
Answer: Y= 8x + 2.8
Step-by-step explanation: slope is 8 (think rise over run) and y-intercept seems to be 2.8, heh hope that helped
Answer:
The surface area of the drum is 3317.5218 square inches.
Step-by-step explanation:
Drum's have a cylindrical form, therefore in order to calculate its surface area we need to apply the correct formula, as shown below:
Where the first term of the sum is the area of the lid and bottom of the drum and the second term is the area of the walls of the drum, r is the radius and h is the height. Applying the data from the problem, we have:
The surface area of the drum is 3317.5218 square inches.
