Answer:
[tex]x = 12[/tex]
Step-by-step explanation:
1) Set up an equation that involves all of the values; the price and kg of each duck and chicken equating to 206.40.
[tex]8.50(x) + 3.60(2x + 5) = 206.40[/tex]
[tex]8.50x + 7.2x + 18 = 206.40[/tex]
2) Solve it.
[tex]15.7x + 18 = 206.40[/tex]
[tex]15.7x = 206.40 - 18[/tex]
[tex]15.7x = 188.4[/tex]
[tex]x = \frac{188.4}{15.7}[/tex]
[tex]x = 12[/tex]
