["Find total units: 4 + 5 = 9 units. Each unit = 90 / 9 = 10 players.","Tennis = 4 x 10 = 40. M:F = 3:1 so female tennis = 1/4 x 40 = 10.","Badminton = 5 x 10 = 50. M:F = 2:3 so female badminton = 3/5 x 50 = 30. Total female = 10 + 30 = 40."]