Ram, who is half as efficient as Krish, will take 30 days to complete a task if he worked alone. If Ram and Krish worked together, how long will they take to complete the task?  Options.
A) 16 days  B) 10 days  C) 8 days  D) 6 days  E) 18 days

Rationale: "number of days taken by ram to complete task = 30 since ram is half as efficient as krish , amount of work done by krish in 1 day = amount of work done by ram in 2 days if total work done by ram in 30 days is 30 w amount of work done by ram in 1 day = w amount of work done by krish in 1 day = 2 w total amount of work done by krish and ram in a day = 3 w total amount of time needed by krish and ram to complete task = 30 w / 3 w = 10 days answer b"
Answer: B