Question 1120515
A town under siege has sufficient food for 200 days at a constant rate of consumption.
 After 50 days, a quarter of the inhabitants escape and those left are put on half rations.
 How many days altogether will the remaining food last?
:
Lets do this assuming their are 100 people in the town originally
Therefore we have: 100 * 200 = 20000 man-days of food available
In 50 days, 100*50 = 5000 man-days have been consumed leaving 15000 man/days
Now we have 75 people and 15000 man/days available
It will take 15000/75 = 200 days to consume the food at full rations
However at half rations it will last 400 days