Question

In a factory, there are 3 workers Ram, Pappu and Kamal. Ram and Pappu can do a work in 15 days while Pappu and kamal can do same work in 25 days and Ram alone can do same work in 30 days , then in how many days to complete if Ram and Kamal work together with 50% efficiency of both
1. 40
2. 50
3. 60
4. 35

Answer 1

Correct Answer - Option 2 : 50

Given 

Ram and Pappu can do work = 15 days 

Pappu and Kamal can same work = 25 days 

Formula Used

Work = time × efficiency 

Calculation 

⇒ Take LCM of (15, 25 and 30) = 450

⇒ let total work be 450

⇒ efficiency of Ram and Pappu = 450/15 = 30 

⇒ efficiency of Pappu and kamal = 450/25 = 18

⇒ efficiency of Ram = 450/30 = 15  

⇒ Ram + Pappu = 30 

⇒ Pappu = 30 - 15 = 15 

⇒ Pappu + kamal = 18 

⇒ so, efficiency of kamal = 18 - 15 = 3 

⇒ Ram+ kamal = 15 + 3 = 18 

⇒ 50% efficiency of Ram + kamal = 18 × (1/2) = 9 

⇒ No. of days taken by Ram and kamal with 50% efficiency = total work/efficiency 

⇒ No. of days = 450/9 = 50 days 

∴ 50 days taken by Ram and kamal with 50% efficiency to complete the work