A camp of soldiers has food for 200 days. After 20 days, 100 more soldiers join the camp and the food now can last for 80 days. What was the initial number of soldiers in the camp?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 80.
Let's assume the initial number of soldiers is 'y'.
A camp of soldiers has food for 200 days. After 20 days, 100 more soldiers join the camp and the food now can last for 80 days.
200y = 20y + 80(y + 100)
200y = 20y + 80y + 8000
200y = 100y + 8000
200y - 100y = 8000
100y = 8000
y = 80
The initial number of soldiers in the camp = 80