Before the use of calculators, mathematicians developed and used detailed tables of values of the sine, cosine and tangent ratios for any given angle. for example: (look the what would have been the main purpose for developing these tables?

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?