A can complete a task in 12 days. B can complete the task in 18 days. If A and B work on this same task in alternate days starting with A, in how many days do they finish the entire task? Choose the correct choice from the following answers
A) 10.8 days
B) 14.33 days
C) 11 days
D) 8.4 days
E) 9.6 days
DETAILED SOLUTION   A can complete a task in 12 days and B can complete the task in 18 days. So,   In one day, A can do 1/12, in one day B can do 1/18.   In two days, they can complete 1/12 + 1/18 = which is 5/36.   In 4 days, they can finish 10/36, and so on.   We can have 7 such sets of 2days each.   So, at the end of 14 days, they would have done 35/36 of task.   On the 15th day A would begin work with 1/36of the task to finish. He can finish 1/12 in a day. So, he would take one-third of a day. So, they can finish the whole task in 14.33 days.   CORRECT ANSWER 14.33 days
<result>B</result>
A can complete a task in 12 days. B can complete the task in 18 days. If A and B work on this same task in alternate days starting with A, in how many days do they finish the entire task?