Question

In pedros town 42% of the houses have both internet service and a home phone. If 82% of all the houses in his town have internet service, what is the probability that a house has a home phone if it has internet service?

Answer 1

Answer: 0.51

Explanation:

We know that:

For a random selection, we have a probability of 0.42 where the house has both services and a probability of 0.82 that the house has only internet service.

Let's suppose that the percentage of houses the houses with internet service (the 82% of the total) that also have a home phone is X

Then we must have that, (X/100%) times the 0.82, must be equal to 0.42

(X/100%)*0.82 = 0.42

X = (0.42/0.82)*100% = 51%

This means that 51% of the houses with internet service, also have a home phone.

Then the probability that a house has a home phone given that it has internet service, is equal to:

51%/100% = 0.51

The probability is 0.51