B completes a work in 8 days. A alone can do it in 10 days. If both work together, the work can be completed in how many days?  Choose the correct choice from the following answers
A) 3.75 days
B) 4.44 days
C) 5 days
D) 6.44 days
E) 7 days

Rationale: "1 / 8 + 1 / 10 = 9 / 40 40 / 9 = 4.44 days answer : b"
Answer: B