Food for 120 people for 1 day=120x
Total available food=120x*200(food available for 200 days for 120 people)
Total food =24000x
Food consumed in 5 days=120x*5=600x
Food left after 5 days=24000x-600x=23400x
As 30 people died after 5 days, remaining people 90
Food required for 90 people for day =90x
No of days food can be consumed for 90 people=food left/food consumption per day
=23400x/90x
=260
So their remaining food will be last for another 260 days .