We know that x = 30 + y, because the problem says that there are 30 more football players than basketball players.
Each group has 10 more members added: x + 10 and y + 10. We can write x + 10 as 30 + y + 10 or 40 + y.
The ratio (40 + y)/(y + 10) = 3/2. You can cross multiply to get:
80 + 2y = 3y + 30
Combine like terms to get:
y = 50 members on the basketball team. Since there are 30 more members on the football team, you just add 30 to 50 to get x = 80 members on the football team.
Well you only do that when you are in the ones place and you have to regroup a 1in the tens place if you go past 19 then you are going to have to regroup a 2
