p = pasari si o = oi
p + o = 120 ⇒ p = 120 - o
2 × p + 4 × o = 298
2 × ( 120 - o ) + 4 × o = 298
240 - 2 × o + 4 × o = 298
2 × o = 298 - 240
2 × o = 58
o = 58 : 2
o = 29 ( oi )
120 - 29 = 91 de pasari
Verific: 91 × 2 + 29 × 4 = 182 + 116 = 298 picioare