Time and Work on Arithmetic Aptitude related Questions and Answers

Question :   Worker A takes 8 hours to do a job. Worker B takes 10 hours to do the same job. How long it take both A & B, working together but independently, to do the same job? 1. 40/9 days 2. 40/7 days 3. 7.5 days 4. 8.5 days Answer :   1 - 40/9 days