Question
Two trains of equal lengths take 15 seconds and 30
seconds respectively to cross a telegraph post. If the length of each train be 180 metres, in what time will they cross each other travelling in opposite direction?Solution
Speed of the first train = [180/15] m/sec = 12 m/sec Speed of the second train = [180/30] m/sec = 6 m/sec Speed = (12 + 6) m/sec = 18 m/sec Required time = (180 + 180)/18 sec = 20 sec
Data warehouse metadata primarily describes:
What is meant by 'cardinality' in data modeling?
A data cube allows analysis by:
Which schema in data warehousing uses a central fact table connected to dimension tables?
In a data warehouse, a fact table typically contains:
What is the main purpose of a data mart?
Which of the following is a real-time data warehouse application?
Which of the following is used to maintain information about the structure of a data warehouse?
What does "drill-down" operation in OLAP do?
Which SQL query will correctly calculate the average salary of employees in each department and group them by department in a table named 'employees'?
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