Answer:
80 % Â
Step-by-step explanation:
Let G₇= games won in 2007
In 2008
G₈ = G₇ + 20 % of G₇
  = G₇ + 0.20G₇
  = G₇(1 + 0.20)
  =1.20G₇
In 2009
G₉ = G₈ + 50 % of G₈
  = G₈ + 0.50G₈
  = G₈(1 + 0.50)
  = 1.50G₈   Substitute the value of G₈
  = 1.50(1.20G₇)
  = 1.80G₇
  = G₇(1 + 0.80)
  = G₇ + 0.80G₇
In 2009, the team won 80 % more games than in 2007.