the correct question is
Michael sold 2/3 of his CDs and purchased 16 more. If Michael has 25 CDs now, how many CDs did he have to begin with?
Let
x--------------> numbers of CDs Michael have to begin
if Michael sold (2/3)x-----------> are pending to sell (1/3)x
we know that
(1/3)x+16=25--------> (1/3)x=25-16-------> (1/3)x=9---------> x=27
the answer is 27 CDs