1. If 72 men can do a piece of work in 25 days, how many days will 30 men do it?

2. If 20 men can reap field in 8 days, then 16 men will reap the same field in how many days?

3. A Train is moving at a uniform speed of 72 Kms. per hour.

a) How far will it travel in 25 minutes? b) Find the time required to cover a distance of 216 Kms.?

4. Walking at a speed of 4 Kms. per hour a man covers a certain distance in 2 hours 4 minutes. If he runs at a speed of 16.5 kmr. per hour, find the time taken by him to cover the same distance?

5. A certain number of men could do a piece of work in 60 days. If there were 8 more it could be finished in 10 days less. Find the number of men in the beginning?

6. If 12 Carpenters can make 480 Chairs in 24 days, how many Carpenters can make 1000 Chairs in 24 days?

Due to paucity of time, we can not provide solutions to all of your questions. We have solved best three out of them. Try to solve rest of the questions on your own. 

Question 1:

It is given that 72 men can do a piece of work in 25 days.

Piece of work done by 72 men in 25 days = 1

⇒ Piece of work done by 72 men in 1 day =

⇒ Piece of work done by 1 man in 1 day =

⇒ Piece of work done by 30 men in 1 day =

∴ Piece of work done by 30 men in 60 day =

Therefore, 30 men can finish the work in 60 days.

Question 3:

(a) 

Distance traveled by train in 1 hour = 72 km

⇒ Distance traveled by train in 60 minutes = 72 km

⇒ Distance traveled by train in 1 minute =

⇒ Distance traveled by train in 25 minutes =

(b)

Time taken to cover 72 kms = 1 hour

⇒ Time taken to cover 1 km =

⇒ Time taken to cover 216 kms =

 

Question 5:

Let the initial number of men be x.

Piece of work done by x men in 60 days = 1

⇒ Piece of work done by x men in 1 day =

⇒ Piece of work done by 1 man in 1 day =

If there were 8 more men i.e., x + 8 men then work could be finished in 10 less i.e., 50 days.

Piece of work done by (x + 8) men in 50 days = 1

⇒ Piece of work done by (x + 8) men in 1 day =

⇒ Piece of work done by 1 man in 1 day =

From the solution, we obtain

=

⇒ 50 (x + 8) = 60x

⇒ 50x + 400 = 60x

⇒ 400 = 10x

x = 40

Thus, initially there were 40 men.

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