Question 1168159
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There is some good basic arithmetic in this problem; but the question that is asked makes no sense....<br>
The camp starts with enough food for 100 students for 30 days.<br>
After the first 2 days, there is enough food for 100 students for 30-2 = 28 days.<br>
Then 40 new students joined the camp.  That means the number of students increased by a factor of 140/100 = 1.4.  And that means the number of days the food will last decreases by a factor of 1.4.  So the food will last the 140 students for 28/1.4 = 20 days.<br>
Then, after the next two weeks (14 days), there will be enough food for the 140 students for 20-14 = 6 days.<br>
At that point, half the students leave the camp.  That means the number of days the food still on hand will last doubles; so there is now enough food on hand for the 70 remaining students for 6*2 = 12 days.<br>
There is nowhere in this scenario where any more food needs to be ordered....<br>