A can do a work in 6 days , B can do a work in 8 days and C can do it in 12 days. B left work after 1 day. For how many number of days should A and C should work together to complete the remaining work ? Choose the correct option:  A) 1 / 7  B) 2 / 7  C) 3 / 7  D) 4 / 7  E) 5 / 7

Rationale: b work 1 / 8 * 1 = 1 / 8 remaining work = 1 - 1 / 8 = 7 / 8 a and c work together = 1 / 6 + 1 / 12 = 3 / 12 = 1 / 4 take reciprocal 7 / 8 * remaining work = 8 / 7 * 1 / 4 = 2 / 7 answer : b
Answer: B