4 women can complete a work in 7 days and 10 children take 14 days to complete the work. How many days will 5 women and 10 children take to complete the work? Select:  A) 4 days  B) 6 days  C) 7 days  D) 9 days  E) 1 days

Rationale: "1 women ' s 1 day work = 1 / 28 1 child ' s 1 day work = 1 / 140 ( 5 women + 10 children ) ' s 1 day work = ( 5 / 28 + 10 / 140 ) = 1 / 4 5 women and 10 children will complete the work in 4 days . answer : a"
Answer: A