Saved Bookmarks
| 1. |
A, B and C can individually complete a task in 20 days, 15 days and 12 days, respectively. A started the work and left after some days. After this B and C worked for 3 days and completes the work. Then find for how many days A has worked in the beginning?1. 11 days2. 9 days3. 13 days4. 15 days |
|
Answer» Correct Answer - Option 1 : 11 days Given: A, B, and C takes 20 days, 15days, and 12 days respectively. B and C worked for 3 days. Formula Used: Total work is the LCM of time taken Efficiency = Total work/Time taken Calculation: Total units of work = LCM of 20, 15, and 12 ⇒ Total units of work = 60 units Efficiency = Total work/Time taken EfficiencyA = 60units/20days ⇒ EfficiencyA = 3 units/day EfficiencyB = 60units/15days ⇒ EfficiencyB = 4 units/day EfficiencyC = 60units/12days ⇒ EfficiencyC= 5 units/day B and C worked for 3 days. Total units of work completed by them, ⇒ Units of work completed = (B + C) × 3 days ⇒ Units of work completed = (4 + 5) × 3 ⇒ Units of work completed = 9 × 3 ⇒ Units of work completed = 27 units Remaining units of work = 60 – 27 ⇒ Remaining units of work = 33 units 33 units of work completed by A in the starting days. ⇒ Number of Days taken A = 33/3 ⇒ Number of Days taken A = 11 days ∴ The number of days A worked for is 11 days. |
|