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# help

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If the farm has 30 chickens and cows, and there are 82 chicken and cow legs all together, then how many chickens and how many cows could the farm have

Jan 18, 2020

#1
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If the farm has 30 chickens and cows,
and there are 82 chicken and cow legs all together,
then how many chickens and how many cows could the farm have

$$\begin{array}{|rcll|} \hline ch + co &=& 30 \\ ch &=& 30-co \\\\ 2*ch + 4*co &=& 82 \\ 2*(30-co) + 4*co &=& 82 \\ 60-2*co + 4*co &=& 82 \\ 60 + 2*co &=& 82 \\ 2*co &=& 82-60 \\ 2*co &=& 22 \quad | \quad :2 \\ \mathbf{\text{cows}} &=& \mathbf{11} \\\\ ch &=& 30-co \\ ch &=& 30-11 \\ \mathbf{\text{chickens}} &=& \mathbf{19} \\ \hline \end{array}$$

Jan 18, 2020