In a stack of CDs, there are 3 types: Rock, Pop and Jazz. There are 2 Rock CDs, x Pop CDs, and (2x+5) Jazz CDs. A CD is chosen at random. If the probability it is Rock is 1/20, work out the probability it is Jazz.

Number of Rock CDs = 2Total Number of CDs = 2 + x + (2x+5) = 3x + 7Probability of Rock CD = 2/(3x + 7) = 1/202/(3x + 7) = 1/2040 = 3x + 7x = 11Number of Jazz CDs = 2x + 5 = 27Total Number of CDs = 3x + 7 = 40Probability of Jazz = 27/40