Question

A garrision of 750 men has provisions for 20 weeks if at the end of 4 weeks,they are reinforced by 450 men,how long will the provision last

Answer 1

After 4 weeks the garrison of 750 men has provisions for 16 weeks
And after reinforcement
Total men 750+450 = 1200
Then provision will last
750/1200*16 = 80/8 = 10

Answer 2

.

750 men : 20 weeks (Given)

.

After 4 weeks:

Provision left = 20 weeks - 4 weeks = 16 weeks

750 men : 16 weeks

.

Number of men after reinforcement arrived:

750 + 450 = 1200 men

.

If there is 1 men:

750 men : 16 weeks

1 man : 750 x 16 weeks

1 man : 12000 weeks

.

If there are 1200 men:

1200 men : 12000 ÷ 1200 weeks

1200 men : 10 weeks

.

Answer: The provision can last for another 10 weeks after the 450 men came.