dhamsha2
Please post the explanation.
ExplanationI.
Percentage of people who completed a bachelor's degree as well as own a house = B + C = 5 + 7 = 12%.
So, the required probability will be 12%/100% = 12%
Hence, 12% is the correct answer choice. II.
Percentage of people who do not carry a high school degree and do not own a house = All those outside of A + B + C + D + E + F + G = outside of 82% = 18%
Hence, 18% is the correct answer choice. An interesting discussion: A student once wrote to us mentioning that the answer to the first part of the question should have been 5% since the question asks for the probability that the resident has completed a bachelor’s degree AND owns a house, and it would have made sense to add the probabilities if the question asked for the probability that the resident has completed a bachelor’s degree OR owns a house.
Can you figure out the flaw in the reasoning?
There are two mistakes in the reasoning:
1. The above reasoning does not take into account that the question specifies “
any person carrying a master’s degree also carries a bachelor’s degree” and hence the resident group “C” also has completed a bachelor’s degree AND owns a house.
2. The terms “AND” and “OR” in the context of probabilities of events seem to have been incorrectly interpreted in the above reasoning. The probability of event
X “AND” Y refers to the probability of both events X and Y happening together. The probability of event
X “OR” Y refers to the probability of at least one of the events occurring. Below are a few examples of probabilities of various events based on the above example:
• Probability that the resident has completed a bachelor’s degree = (C + B) + (E + F)
• Probability that the resident owns a house = G + (C + B)
• Probability that the resident has completed a bachelor’s degree AND owns a house = (C + B)
• Probability that the resident has completed a bachelor’s degree OR owns a house = G + (C + B) + (E + F)