Question

The probability that a patient visiting a dentist will have a tooth extracted is 0.06, the probability that he will have a cavity filled is 0.2 and the probability that he will have a tooth extracted as well as cavity filled is 0.03 ? What is the probability of that a patient has either a tooth extracted or a cavity filled ?

• A. $0.15$
• B. $0.23$
• C. $0.03$
• D. $0.95$

Answer 1

Answer: (B)

$0.23$

Let A be the event that the patient will have his tooth extracted, B the event that he will have a cavity filled.

We have, $P\left(A\right)=0.06,P\left(B\right)=0.2$ and $P(A\cap B)=0.03$

Therefore,

Required probability = $P(A\cup B)=P\left(A\right)+P\left(B\right)-P(A\cap B)=0.06+0.2-0.03=0.23$