IBPS SO Prelims Exam Model Paper 1

Given:
Garrison started from 2nd of January 2019
Initial number of soldiers = 500
Time = (2nd January to 28th February) = (30 + 28) = 58 days
After 20 days 60% of soldiers left the garrison
Concept:
In this type of question always consider that every soldier eats 1 unit of food each day. And using this calculates the total food available in garrison.
Calculation:
Let each soldier consume 1 unit of food every day
So the total food available in garrison = 500 × 58 = 29000 units
After 20 days 60% of soldier left
Now, the remaining food = 29000 – 500 × 20 = 19000 units
And remaining soldier = 40% of 500 = 200
∴ Time for which they would carry on with the remaining food =

19000

200

= 95 days