Apple harvest

The father would pick all the apples himself in 8 days. After two days, the son also started harvesting, and after another four days, they finished harvesting. How much would his son pick all the apples for?

Final Answer:

s =  16

Step-by-step explanation:

$$\begin{gathered} o=8 \\ \frac{1}{o}\cdot 2+4\cdot (\frac{1}{o}+\frac{1}{s})=1 \\ s\cdot \frac{2}{o}+4\cdot (\frac{s}{o}+1)=s \\ 2\cdot s/o+4\cdot s/o+4=s \\ 2\cdot s/8+4\cdot s/8+4=s \\ 2s=32 \\ s=\frac{32}{2}=16 \\ s=16 \end{gathered}$$

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