As the ratio of the money with Sean and Joe was 3:5 initially, we can say Sean had 3x and Joe had 5x.

After Sean spends $15 he has 3x - 15. After Joe spends $35 he has 5x - 35.

As these are equal, we get

3x - 15 = 5x - 35

=> 2x = 20

=> x = 10

**Initially Sean had $30 and Joe had $50.**