Question

A history teacher places the names of her class members in a box for a question-and-answer session. If the class contains 8 boys and 16 girls and the names are selected at random and not replaced, what is the probability that the first two questions will go to girls?(1 point)
Responses

1023
10 over 23

49
4 ninths

308
30 eighths

512

1 answer

To find the probability that the first two questions will go to girls, we can follow these steps:

  1. Total students in the class: There are 8 boys and 16 girls, giving us a total of 8 + 16 = 24 students.

  2. Probability that the first question goes to a girl: \[ P(\text{first question to a girl}) = \frac{\text{number of girls}}{\text{total students}} = \frac{16}{24} = \frac{2}{3} \]

  3. Probability that the second question goes to a girl following the first: If the first question went to a girl, then there are now 15 girls left out of a total of 23 students (since one girl was already selected). \[ P(\text{second question to a girl}) = \frac{\text{number of girls left}}{\text{total students left}} = \frac{15}{23} \]

  4. Combined probability: The probability of both events happening (first and second questions going to girls) is: \[ P(\text{both questions to girls}) = P(\text{first question to a girl}) \times P(\text{second question to a girl}) = \frac{16}{24} \times \frac{15}{23} = \frac{2}{3} \times \frac{15}{23} = \frac{30}{69} = \frac{10}{23} \]

Thus, the probability that the first two questions will go to girls is: \[ \frac{10}{23} \]

The correct response is 10 over 23.