4 men and 6 women finish a job in 8 days, while 3 men and 7 women finish it in 10 days. In how
many days will 10 women working together finish it ?  Options.
A) 30 days B) 40 days C) 50 days D) 60 days E) 70 days

Rationale: explanation : let 1 man ' s 1 day work = x and 1 woman ' s 1 days work = y . then , 4 x + 6 y = 1 / 8 and 3 x + 7 y = 1 / 10 solving , we get y = 1 / 400 [ means work done by a woman in 1 day ] 10 women 1 day work = 10 / 400 = 1 / 40 10 women will finish the work in 40 days option b
Answer: B