I think it’s the last one but I’m not sure
Answer: The required probability is 0.1923.
Step-by-step explanation:
Since we have given that
Probability that it's a good dog = 0.4
Probability that it's a bad dog = 1-0.4 = 0.6
Probability that the dog smokes given that its a bad dog = 0.7
Probability that it smokes given that its a good dog = 0.25
According to question, probability of smoking pipe would be
P(good).P(Smoking pipe|good)+P(bad).P(smoking pipe|bad)

So, Probability of getting a good dog given that it is smoking pipe is given by

Hence, the required probability is 0.1923.
Rationalizing the denominator, simply means "getting rid of that pesky root at the bottom", and we do so by simply multiplying it by something to take it out, of course, we multiply the bottom, we have to also multiply the top,


therefore, the Correct choice is d) 15