Correct Answer - Option 3 : 12.75 days

**Given:**

Two-third work is completed by G in 17 days.

H is twice as efficient as G.

**Concepts used:**

Time = Work/Efficiency

1 day work of individual = Work/Time

**Calculation:**

Two-third work is completed by G in 17 days.

⇒ Efficiency of G = Work/Time

⇒ Efficiency of G = (2/3)/17 = 2/51

H is twice as efficient as G.

⇒ Efficiency of H = 2 × 2/51 = 4/51

Time = Work/Efficiency

⇒ Time taken by H to complete full piece of work = 1/(4/51) days = 51/4 days = 12.75 days

**∴**** H completes full piece of work in 12.75 days.**