Answer:
The correct option is B. 23%
Step-by-step explanation:
Let the event that patient brushes his teeth at least twice a day is denoted by A
So, P(A) = 0.83
Let the event that patient flosses daily is denoted by B
So, P(B) = 0.47
Now, it is given that 19 percent patients brush at least twice a day and floss daily.
⇒ P(A and B) = 0.19
Now, we need to find conditional probability of occurring event B given A has occurred.
Hence, Nearest required percentage = 23%
Therefore, The correct option is B. 23%