Marc Has 45 CDS

Question

Marc has 45 CDs in his collection, and Corinna has 61. If Marc buys 4 new CDs each month and Corinna buys 3 new CDs each month, after how many months will Marc and Corinna have the same number of CDs?

Answer 1

m=45, c= 61

45+4m = 61+3m

m = 61-45 = 16 months = 1 1/3 year when they both have the same