Question 729613
Let us assume that each man of garrison consumes x gms provision per day					
80 men shall consume 80*x gms per day					
in 10 days they shall consume 80*x*10 or 800x gms					
Now for two days 80 persons shall consume 2*80*x gms					
therefore for remaining days the provisions in balance is  800x-160x=640x gms					
This 640x gms quota is consumed by (80+additional men who joined after two days) in 4 days					
Therefore No.of people=640/4=160					
So 80 additional men joined the garrison after two days