A carpenter worked alone for 1 day on a job that would take him 7 more days to finish. He and another carpenter completed the job in 4 more days. How many days would it have taken the second carpenter to do the complete job working alone?	Choose the correct choice from the following:
A) 16
B) 7
C) 9
D) 14
E) 24

Rationale: "a carpenter worked only 1 day on something that takes him 7 more days . means ; carpenter finishes his work in 8 days . let his buddy finish the same task in x days . respective rates per day : 1 / 8 and 1 / x to complete 1 work : first guy worked for 5 days @ rate = 1 / 8 per day . second one worked for 4 days @ rate = 1 / x per day expression : days * rate = work 5 * 1 / 8 + 4 * 1 / x = 1 5 x + 32 = 8 x 2 x = 32 x = 16 days . ans : a"
Answer: A