Whats 67000000000000 x 10 to the number of 12?

What is the rule for reflection across the y axis

See attachment below and find the equivalent of tan(∠qsr)

Aclassroom is made up of 11 boys and 14 girls. the teacher has four main classroom responsibilities that she wants to hand out to four different students (one for each of the four students). if the teacher chooses 4 of the students at random, then what is the probability that the four students chosen to complete the responsibilities will be all boys?