37.5 minutes
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To find out how long it will take the waiter to set 1 table, divide the time taken to set 8 tables by 8:
Since there are 30 tables in total, multiply the time taken to set 1 table by 30 to find the total time it will take to set all the tables:
So, it will take 37.5 minutes the waiter to set all the tables in the dining room.