To calculate the probability that a person selected at random from the group will be a male given that the person is over 30 years old, we need to determine the number of males over 30 and the total number of people over 30 in the group.
From the given information, we know that there are:
- 9 males over the age of 30.
- 6 females over the age of 30.
To find the total number of people over 30, we can add the number of males and females over 30:
Total number of people over 30 = 9 males over 30 + 6 females over 30 = 15 people over 30.
Now, we can calculate the probability of selecting a male over 30 by dividing the number of males over 30 by the total number of people over 30:
Probability of selecting a male over 30 = Number of males over 30 / Total number of people over 30
= 9 males over 30 / 15 people over 30
Therefore, the probability that a person selected at random from the group will be a male given that the person is over 30 years old is:
9/15, which simplifies to 3/5 or 0.6 (60%).