A] The author of the novel 'The Corrections' is Jonathan Franzen. B] The author of the novel 'A Visit from the Goon Squad' is Edward P Jones. C] The author of the novel 'Forty Thieves' is Thomas Perry.
X, Y and Z can do a piece of work in 30,40 and 50 days respectively. All three of them began the work together but Y left 4 days before completion of the work. In how many days was the work completed?