In a garrison, there was food for 1000 soldiers for one month. After 10 days 1000 more soldiers joined the garrison How long would the soldiers be able to carry on with the remaining food?

According to question ,
3 pumps working in 2 days = 8 × 2 = 16 hours
It means that they can empty a tank in 16 hours .
3 pumps 1 hour work = 1/16
1 pumps 1 hour work = 1/( 3 × 16 )
4 pumps 1 hour work =4 × 1/( 3 × 16 ) = 1 / 12
Hence , they will empty the tank in 12 hours .

Suppose the food will last for D days at same rate .
250 men had provisions for 40 days.
( 250 - 50 ) men had provisions for D days.
Less men, More days ( Indirect Proportion )
we can write as :-
? 200 : 250 :: 40 : D ? (200 × D ) =( 250 × 40 )
? ( 250 × 40 ) /200 = 50
Therefore , 50 days is required answer .

Let the remaining food will last for D days.
500 men had provisions for (27 ? 3) = 24 days.
( 500 + 300 ) men had provisions for D days.
More men, Less days ( Indirect Proportion )
we can write as :-
? 800 : 500 :: 24 : x ? (800 × D ) =( 500 × 24 )
? ( 500 × 24 ) /800 =15
Therefore , 15 days is correct answer .

Given in the question,
Let y be the persons there originally .
Work done by y persons can finish = 100 days
If there were 10 persons less, it would take more days finish the work in 10 days
i.e. ( y - 10 ) = 110
According to question ,
y × 100 = ( y - 10 ) × 110
? 100y = 110y - 1100 ? 10y = 1100 ? y = 110
Therefore , 110 persons were there originally .

Let man's 1 day's work = 1/m
and boy's 1 day's work = 1/n
1 day's work man and boy = 1/24
Man's 6 day's work = 6/m
Now, for 20 days, both man and boy do the work and for last 6 days, only man does the work.
According to the question,
1/m + 1/n = 1/24
? 20(1/m + 1/n) + 6/m = 1
? 20 x (1/24) + 6/m = 1
? 6/m = (1 - 20/24) = 4/24 = 1/6
? 1/n = 1/36
Now from eq. (i)
1/m + 1/n = 1/24
1/36 + 1/n = 1/24
? 1/n = (1/24) - (1/36) = 1/72
Hence, the boy alone can do the work in 72 days.

Let 15 men work for m days.
Work done in 1 days = m/20
Remaining work = (1 - m/20)
25 men's 1 days work = 1/20
1 man's 1 days work = (1/20) x (1/25) = 1/500
10 men's 1 days work = 10/500 = 1/50
10 men's 75/2 days work = (1/50) x (75/2) = 75/100 = 3/4
? (1 - m/20) = 3/4
? m/20 = 1/4
? m = (1/4) x 20 = 5
Clearly, 15 men leave after 5 days.

12 men ? 18 women
? 1 man ? 18/12 women ? 3/2 women
? 8 men ? (3/2) x 8 = 12 women
? 8 men + 16 women = 12 women + 16 women = 28 women
? 18 women can do the work in 14 days .
? 1 woman can do the same work in (14 x 18) days.
? 28 women will do the same work in (14 x 18)/28 days.
? Required number of days = (14 x 18)/28 = 9 days