Agroup of students consists of 15 piano players and 3 guitar players. a sample of seven is selected at random. what is the probability that at least one guitar player is chosen?

School has 204 sixth grade students. if the sixth grade is 30% of the total school, how many students are in the middle school?

y=2x−1 5x−4y=1 is (1,1)(1,1) a solution of the system?

The diameter of the moon is about 3500 km. approximate the surface area of the moon using the formula for the surface area of a sphere, s = 4πr2. write your answer in scientific notation.