A fort had enough food for 80 soldiers for 60 days .How long would the food last if 20 more soliders join after 15 days ?

A total of 51 days, or 36 days after the extra soldiers join in.

Step-by-step explanation:

Let's say a soldier eats 1 portion of food in 1 days. That portion may be divided into breakfast, lunch , and dinner, but it is still accounted as 1 portion per soldier per day.

There are 80 soldiers and enough food for 60 days.

The number of portions is

60 * 80 = 4800

The fort started with 4800 portions.

80 soldiers ate their portions for 15 days.

80 * 15 = 1200

After 15 days, they have

4800 - 1200 = 3600 portions left.

After 15 days, 20 more soldiers joined in.

Now there are 80 + 20 = 100 soldiers.

There are 3600 portions left for 100 soldiers.

3600/100 = 36

The food would last 36 days after the 15 days, or a total of 51 days.

y > 1/3x

y < = -x + 4

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