9/20
explanation:
7/10 - 1/4
14/20 - 5/20
14-5/20
9/20
Answer:
B. 9,000,000,000
Step-by-step explanation:
From the given information:
We are to determine the best estimate of the number of bottles sold this year and last year.
The best estimate means rounding up to the nearest whole number.
Given that:
7,234,267,990 bottles of water were purchased this year
2,000,900,999 bottles of water were purchased last year
The estimate of the bottles sold this year and last year from the above value is:
= 7,000,000,000 + 2,000,000,000
= 9,000,000,000
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
Since there is two negative signs in the original equation, you need two negative signs in the equivalent one as well.
Because one of the negatives if before the fraction, it doesn't matter if the second negative is on the 13 or on the 12.
The answer is A.
