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?  Choose the correct option:
A) 20 / 9	B) 40 / 9	C) 50 / 9	D) 60 / 9	E) 80 / 9

Rationale: "one day work of a = 1 / 8 one day work of b = 1 / 10 so one day work of a and b together = 1 / 8 + 1 / 10 = 9 / 40 so total days required = 40 / 9 answer : b"
Answer: B