Working individually, Emma can wrap presents for 6 hours and Troy can wrap presents in 8 hours. If Emma and Troy work together but independently at the task for 2 hours, at which point Troy leaves, how many remaining hours will it take Emma to complete the task alone? Choose the correct choice from the following answers
A) 30 / 12  B) 5 / 12  C) 3 / 4  D) 2 / 12  E) 3 / 5

Rationale: in first 2 hrs troy will finish 2 / 8 = 1 / 4 of work and emma will finish 2 / 6 work so total 1 / 4 + 1 / 3 = 7 / 12 work is finished and 1 - 7 / 12 = 5 / 12 work remaining . now emma will take ( 5 / 12 ) * 6 = 30 / 12 hrs to finish it . so answer is a .
Answer: A