Hens

13 hens are eating spilled grain, which is estimated to last from 6 AM to 4 PM. At 11 o'clock, grandmother brought 5 more hens from the neighbours.

At what time was all the grain eaten?

Result

h = 14:37 hh:mm

Step-by-step explanation:

$$\begin{gathered} d=\frac{16-11}{10}=\frac{1}{2}=0.5 \\ s=\frac{1}{10\cdot 13}=\frac{1}{130}\doteq 0.0077 \\ {t}_1=\frac{d}{s\cdot (13+5)}=\frac{0.5}{0.0077\cdot (13+5)}=\frac{65}{18}\doteq 3.6111\text{h} \\ h=11+t_1=11+3.6111=14.61111=14:37\text{hh}:\text{mm} \end{gathered}$$

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