franklin is thinking of two numbers. the sum of the two numbers is 40.the first number x, is 11 less than twice the second number, y. which system of equations can be used to find the two numbers? A) xy=40, x=2y-11 B) x+y=40, x=11-2y C) x-y=40, x=11-y D)x+y=40, x=2y-11

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?

The sum of five and a number n is at least 12

The coverage of a base station of a telecommunication company forms a disk with a radius of (kilometers). let be the distance of a cellphone from a base station. assume that the location of cellphones in use are randomly uniformly distributed within the disk. calculate the mean and variance for the random variable.