Option 3 : 14 days

**Given:**

Efficiency of Avesh is more than Rohit by 40%

Efficiency of Rohit is more than Williamson by 25%

Time taken by Avesh to complete the work = 8 days

**Concept used:**

Efficiency is inversely proportional to the time

**Calculation:**

Let the efficiency of rohit be 100%

Then,

Efficiency of Avesh = (100 + 40)% of Efficiency of Rohit

⇒ Efficiency of Avesh/Efficiency of Rohit = 140/100

⇒ Efficiency of Avesh/Efficiency of Rohit = 7/5

Efficiency of Rohit = (100 + 25)% of efficiency of Williamson

⇒ Efficiency of Rohit/Efficiency of willliamson = 125/100

⇒ Efficiency of Rohit/Efficiency of willliamson = 5/4

From above we can say,

Efficiency of Avesh = 7units /day

Efficiency of Rohit = 5 units/day

Efficiency of Williamson = 4 units/day

Avesh can complete the work in 8 days,

Total work = 7 × 8 = 56 units

Time taken by Williamson to complete the work = 56/4

⇒ Time taken by Williamson to complete the work = 14 days

**∴ The time taken by Williamson to complete the work is 14 days.**