The product of six and a number x

Marina baked cookies. she gave 3/4 of the cookies to the scout bake sale. she shared the remaining 6 cookies with her friends. how many cookies did marina bake?

Diane’s bank is offering 5% interest, compounded monthly. if diane invests $10,500 and wants $20,000 when she withdrawals, how long should she keep her money in for? round to the nearest tenth of a year.

60 musicians applied for a job at a music school. 14 of the musicians play both guitar and drums, 28 play drums, 18 play the guitar. what is the probability that the applicant who gets the job plays drums or guitar?