Question

jagdish can build a wall in 10 days. narender can build same wall in 12 days while sumit takes 15 days to do the same the job. which two of them should be employed to finish the job in 6 days?

Answer 1

So,

Here is direct method to solve this type of problems,

If days taken by A to complete a task is x and y is the number of days taken by B to complete the same task, then if they work together they can complete the task in

(x × y)/(x + y) days

(Harmonic mean)

Now, the question wants us to find the combination such that the task is completed in exactly 6 days

So if we take the value of days taken by Jagdish and Sumit we get,

=(10 × 15)/(10+15)

=150/25

=6

So,

Jagdish and Sumit must be employed to complete the job in 6 days

Hope this helps !!!!!!!!!!!!