For what value of k will k + 9, 2k -1 and 2k + 7 are the consecutive terms of an A. P.?

If sr is 4.5cm and tr is 3cm, what is the measure in degrees of angle s?

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?

60 musicians applied for a job at a music school. 14 of the musicians play both guitar and drums. what is the probability that the applicant who gets the job plays drums or guitar?