唔該！
p.9（32，33）p.（31,32)p.39(27,28,29,30,31)p.57(16,17,18,19)
要題解和式和答案！！！！！
更新1:
要快，please！！！！！
更新2:
1.In a ferry pier,ferries set off for islands A ,B and C every 25,45 and 75 minutes respectively. At 10:00a.m.,ferries set off from the pier for all the three islands.when will they set off again at the same time if the ferry services end at 11:00p.m.every day?List all the possible cases.