p = 2c
4p + 2c = 200
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Inlocuim p in ec, 2
4 × 2c + 2c = 200
8c + 2 c = 200
10c = 200
c = 200 / 10 = 20 de curcani
p = 2c = 2 × 20 = 40 de purcei
