Question

120 students of a hostel have food enough for 60 days.If 30 more students join the hostel after 15 days how long does remaining food last?

Answer 1

Step-by-step explanation:

Lets say they have 16000 kg food or x kg

( understand without ”x” first, only consider 16000 kg)

120 students —— 60 days —— 16000kg —— x

120 students —— 15 days —— 4000 kg —— x/4

30 students —— 15 days —— 1000 kg —— x/16

150 students —— 15 days —— 5000 kg —— x/4 + x/16 —— 5x/16

Now, 120 students eat for 15 days

so they eat 4000 kg —— x/4

and then we have 150 students, but the food is 12000 kg now —— 3x/4 or 12x/16

we know that

150 students —— 15 days —— 5000 kg —— 5x/16

150 students —— 3 days —— 1000 kg—— x/16

now the food left was 12000 kg so

150 students —— 36 days —— 12000kg (12x/16),

So, the food will last for 36 more days instead of 45 days.

I took 16000 because 120/30 is 4/1

so i’ll need to divide by 4.

I could’ve taken 4000 or 12000 or 400 or 1200 or anything,

that doesn’t matter.

Answer 2

Answer:

120 students — 60 days — 16000kg — x

120 students — 15 days — 4000 kg — x/4

30 students — 15 days — 1000 kg — x/16

150 students — 15 days — 5000 kg — x/4 + x/16 — 5x/16

Now, 120 students eat for 15 days

So, they eat 4000 kg — x/4

and then we have 150 students, but the food is 12000 kg now — 3x/4 or 12x/16

We know that

150 students — 15 days — 5000 kg — 5x/16

150 students — 3 days — 1000 kg— x/16

Now the food left was 12000 kg

So, 150 students — 36 days — 12000kg — 12x/16

So, the food will last for 36 more days instead of 45 days.

I took 16000 because 120/30 is 4/1

So, divide by 4.

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