Bilangan p dan q berbanding senilai. P = 7,5 jika q = 15. Nilai p , jika q = 38, adalah

P = 7.5
Q = 15
p = ......
q = 38
P / p = Q / q
7.5 / p = 15 / 38
p x 15 = 38 x 7.5
15p = 285
p = 285 / 15
   = 18