A and B can complete a task in 20 days, B and C can complete it in 30 days while C and A can do the same task together in 24 days. How many days will each of and C take to complete the task individually?
In a certain code, 327 means 'don't cut tree', 635 means 'plant one tree', 138 means 'tree gives shade' and 4953 means 'we must plant tree'. Which digit represents 'shade'?