A series is given, with one word missing. Choose the correct alternative from the given ones that will complete the series. Oxygen, Toil, Arouse, Arson, Tenuous, ?
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?