lagi, maaf ya kalau merepotkan

Misal :
x = harga ayam betina
y = harga ayam jantan
z = harga itik jantan

5x = 4y....(pers.1)
3y = 4z....(pers.2)

3y = 4z
3y = 4 (75.000)
3y = 300.000
y = 300.000/3
y = Rp.100.000

5x = 4y
5x = 4y
5x = 4 (100.000)
5x = 400.000
x = 400.000/5
x = Rp.80.000

Harga 2 ayam betina
= 2 x 80.000
= Rp.160.000