Provisions for one student =250×35=8750 250 students used provisions for 5 days. Total provisions used by 250 student in 5 days =250×5=1250 Remaining provision =8750−1250=7500 After 5 days total number of student =250+25=275 Total provisions used by 275 student in 10 days275×10=2750 Now Remaining =7500−2750=4750 After 15 days no. of student =275−25=250 4750=250× no. of extra days No. of extra days =