How do I set this up and solve it?

Tom has a collection of 30 CDs and Nita has a collection of 15 CDs. Tom is adding 1 CD a month to his collection while Nita is adding 4 CDs a month to her collection. Find the number of months after which they will have the same number of CDs.

3 answers

Tom 30 + n
Nita 15 + 4 n

30 + n = 15 + 4 n

15 = 3 n

n = 5
Umm that is not a choice
T= 30 CD’s(+1/monthly)
N=15 CD’s(+4/monthly)
30,31,32,33,34,35
15,19,23,27,31,35
It took them 6months to get even.