A, Band C can do a piece of work in 11 days, 45 days and 55 days respectively, working alone. How soon can the work be done if A is assisted by Band C on alternate days?	Choose the correct choice from the following choices:
A) 7 days
B) 8 days
C) 9 days
D) 10 days
E) 11 days

Rationale: "( a + b ) ' s 1 day ' s work = 1 / 11 + 1 / 45 = 56 / 495 ( a + c ) ' s 1 day ' s work = 1 / 11 + 1 / 55 = 6 / 55 work done in 2 day ' s = 56 / 495 + 6 / 55 = 2 / 9 2 / 9 th work done in 2 days work done = 9 / 2 * 2 = 9 days answer : c"
Answer: C