Pak bintang mepunyai kebun seluas 420m2, kebun tersebut ditanami mawar 3/7 bagian dan melati 1/3 bagian, jika sisanya ditanami anggrek, maka luas kebun yg ditanami anggrek adalah
cheonki
L kebun anggrek = 3/7 + 1/3 = 9/21 + 7/21 = 16/21 = 21/21 - 16/21 = 5/21 = 5/21 x 420 = 5/7 x 140 = 5/1 x20 = 100 m²
= 21/21 - 16/21
= 5/21
= 5/21 x 420
= 5/7 x 140
= 5/1 x20
= 100 m²