Answer: 44 soccer, and 55 basketball.
Step-by-step explanation: This is one method that I used: Round up to 100 boys. Add a 0 to both 4 and 5, leaving 40 and 50. Add 5 to each one since it is 100, leaving 45 and 55. Since it still has to be 99 and soccer is lesser, take 1 away from 45 leaving 44 soccer and 55 basketball players.