There are 9 students in a class: 2 boys and 7 girls. if the teacher picks a group of 4 at random, what is the probability that everyone in the group is a girl?

Step-by-step explanation:

In this problem we have independent events, that is, the event "picking a girl" doesn't affect an "picking a boy", also, picking picking a girl doesn't affect the probability of the other subjects.

So, the probability when the first girl is being picked is:

Because among the total 9 students, there are 7 girls.

Now, after picking one girl, there remains 6 girls and 8 students to be picked. So, the probability of the second girl would be:

Then, the probability of the third girl:

The fourth girl probability:

Therefore, the probability of picking all 4 girls would be the product of each probability, because events are independent (we use product when they are independent):

Therefore, there's 28% probability that every student in the group is a girl.

answer: the two figures are congruent.

step-by-step explanation: they're congruent because figure efgh is reflected across the x and y axis but it was also rotated.

hope it !