There exists a grassy field that contains no other food. 11 goats could last there for 7 days before they run out of food. 10 goats could last 8 days there. How long could 3 goats survive there?
If you have not tried to solve it, have a go now. For everyone else the answer is after the break.
In the first scenario there are 77 goat days of food. In the second case, there is 80 goat days. Therefore the field produces enough grass each day to sustain 3 goats, and so the 3 goats could live there forever.
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