A is half good a work man as B and together they finish a job in 26 days. In how many days working alone B finish the job? Choose the correct choice from the following answers
A) 98 days
B) 21 days
C) 17 days
D) 39 days
E) 19 days

Rationale: "wc = 1 : 2 2 x + x = 1 / 26 = > x = 1 / 78 2 x = 1 / 78 = > 39 days answer : d"
Answer: D