Time and Work on Arithmetic Aptitude related Questions and Answers

Question :   X can do a work in 40 days. He worked for 8 days and then Y finished it in 16 days. If they work together, how long does it take to finish the work? 1. 10 1/3 days 2. 18 1/3 days 3. 13 1/3 days 4. 15 1/3 days Answer :   3 - 13 1/3 days