A can do a work in 16 days, B can do it in 24 days, and C can do it in 48 days. How long will they take to complete the work together?
Answer: B. 6 days
A's rate is 1/16, B's is 1/24, and C's is 1/48. Together, they work at a rate of 1/16 + 1/24 + 1/48 = 1/8. Thus, they will complete the work in 8 days.