Question

In the normal course, Ravi, Sanjay and Mukund can each individually build a wall in 5, 8 and 10 days respectively. Due to difficult terrain and slushy conditions at the site, the individual time required for each to complete the work has increased by 20%, 25% and 50% respectively. How long will they take to build the wall if they work together?

Answer 1

Hi,

Answer:

They will take 3 days to build the wall if they work together.

Step-by-step explanation:

Given data:

Ravi can alone build the wall in 5 days.

Sanjay can alone build the wall in 8 days.

Mukund can alone build the wall in 10 days.

Due to climatic changes the individual time required for each to complete the work has increased to 20%, 25% & 50% respectively.

To find: time required to build the wall if Ravi, Sanjay & Mukund work together.

Since the individual time required to build the wall has increased due difficult terrain and slushy conditions at site.

The new time taken by three of them individually will be  

Ravi can alone build the wall in = (120/100) * 5 = 6 days.

Sanjay can alone build the wall in = (125/100) * 8 = 10 days.

Mukund can alone build the wall in = (150/100) * 10 = 15 days.

So, in 1 day

Ravi can do = (1/6)th of work

Sanjay can do = (1/10)th of work

Mukund can do = (1/15)th of work

∴Total work done in 1 day if three of them work together = 1/6 + 1/10 + 1/15 = 10/30 = 1/3

By unitary method, we can get

If 1/3rd of whole work is done in 1 day.

Then,  

The whole work will be done in = 1/(1/3) = 3 days.

∴Total time required by Ravi, Sanjay & Mukund to build the wall, if they work together = 3 days.

Hope this helps!!!!!!

Answer 2

Answer:

Ravi takes 5 normal days to complete the work but due to difficult conditions on the site, his time increases by 20%, i.e.,

20/100 of 5 = 1

5 + 1 = 6 days in difficult situation.

Sanjay takes 8 normal days to complete the work but due to difficult conditions on the site, his time increases by 25%, i.e.,

25/100 of 8 = 2

8 + 2 = 10 days in difficult situation.

Mukund takes 10 normal days to complete the work but due to difficult conditions on the site, his time increases by 50%, i.e.,

50/100 of 10 = 5

10 + 5 = 15 days in difficult situation.

So now, 1/6 + 1/10 + 1/15 = total time taken if they work together

= (5+3+2)/30

= 10/30

= 1/3

Therefore, they will together take 3 days to complete the work.

Hope the answer helps.

Thank you !!!