What is the LCD of 1/4 and 7/12

65% of students in your school participate in at least one after school activity. if there are 980 students in you school, how many do not participate in an after school activity?

An elevator travels 310 feet in 10 seconds. at that speed, how far can't his elevator travel in 12 seconds?

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.