Worker A takes 4 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?	Choices
A) 20/9  B) 40/9  C) 40/14  D) 60/9  E) 80/9
one day work of A = 1/4   one day work of B = 1/10   so one day work of A and B together = 1/4 + 1/10 = 14/40   so total days required = 40/14   ANSWER:40/14
<result>C</result>
Worker A takes 4 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?