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

Jagdish can build a wall in 10 days

⇒ 1 day = 1/10

Narender can build same wall in 12 days

⇒ 1 day = 1/12

Sumit can build same wall in 15 days

⇒ 1 day = 1/15

Number of days need if Jagdish and Narender need to finish the work:

1 day = 1/10 + 1/12 = 11/60

Number of days needed = 60 ÷ 11 = 5.45 days

Number of days need if Narender and Sumit need to finish the work:

1 day = 1/12 + 1/15 = 3/20

Number of days needed = 20 ÷ 3 = 6.67 days

Number of days need if Jagdish and Sumit need to finish the work:

1 day = 1/10 + 1/15 = 1/6

Number of days needed = 6 ÷ 1 = 6 days

Answer: Jagdish and Sumit  should be employed if they want the job to be completed in 6 days.