Consider the given statement as true and decide which of the given conclusions can definitely be drawn from the given statements.
Statement:
All rivers are holy. All gods are holy.
Conclusion:
1. All rivers are gods.
2. All gods are rivers.
A can complete a task alone in 8 days, while B takes 12 days to do it by herself. Together with C it takes them 4 days to complete the work. If C and D together can complete the task in 15 days, then how many days will D need to complete the task by herself?