Answer:
7
The 6 is in the tenths place and the 7 is in the ones place.
Since it is stated that the machine he bought only predict about 80%. Thus, about 20% are still possible that there are oils in the land that he owned.
In a 100% value = 80% were the 0 possibillites detected by the machine and 20% are still the possibility that it has an oil.
=> 80% = 0.80
=> 20% = 0.20
In the given choices. letter B has the closest value to the 20% that we expected.
Thus, let's have B as an answer.
Answer: The answer would be $50. Hope this helps :)
Step-by-step explanation:
1
P(V|A) is not 0.95. It is opposite:
P(A|V)=0.95
From the text we can also conclude, that
P(A|∼V)=0.1
P(B|V)=0.9
P(B|∼V)=0.05
P(V)=0.01
P(∼V)=0.99
What you need to calculate and compare is P(V|A) and P(V|B)
P(V∩A)=P(A)⋅P(V|A)⇒P(V|A)=P(V∩A)P(A)
P(V∩A) means, that Joe has a virus and it is detected, so
P(V∩A)=P(V)⋅P(A|V)=0.01⋅0.95=0.0095
P(A) is sum of two options: "Joe has virus and it is detected" and "Joe has no virus, but it was mistakenly detected", therefore:
P(A)=P(V)⋅P(A|V)+P(∼V)⋅P(A|∼V)=0.01⋅0.95+0.99⋅0.1=0.1085