Sagot :
Let x = the amount of food per person per day.
Then, the total amount of food, n, is:
n = 120 × 200 × x
n = 24000x.
Now, after 5 days, the remaining food, f, is:
f = n-(5 × 120 × x)
= n – 600x
Plug in n = 24000x.
f = 24000x – 600x
f = 23400x.
Now, the amount of food per day, m, is:
m = (120 – 30) × x = 90x
Thus, the remaining food will last for.
[tex]\sf\large{ \frac{f}{m} = \frac{23400x}{90x}}[/tex]
= [tex]\sf\large{ \frac{260\:×\:\cancel{90x}}{\cancel{90x}}}[/tex]
= 260
Answer: 260 days