Jika jmlh penggemar spk bola 120 orang maka banyak siswa yg gemar catur

[tex]catur = 100 - (10 + 40 + 15 + 25) \\ = 100 - 85 = 15\% \\ catur = \frac{15}{40 } \times 120 = 45 \: anak[/tex]

Persentase catur=100%-(10%+25%+15%+40%)
=100%-90%
=10%

Jumlah penggemar catur=10%/100%×120
=12