Question
Train ‘A’ can cross a pole in 8 seconds and a 80
metre long platform in 12 seconds. If the ratio of length of train ‘A’ and train ‘B’ is 2:5, respectively, then find the time taken by train ‘B’ to cross a pole with a speed of 25 m/s.Solution
Let the length and speed of the train ‘A’ be ‘l’ metre and ‘s’ m/s, respectively. According to question, l = 8s Also, 12s = 8s + 80 Or, 4s = 80 Or, s = 20 Therefore, length of train ‘A’ = 8s = 160 metres Length of train ‘B’ = 160 × (5/2) = 400 metres Required time taken = 400 ÷ 25 = 16 seconds
Surrogate keys are used in data warehouses because:
Which SQL clause is used to filter records after aggregation?
ETL stands for:
Which of these is not a typical data warehouse characteristic?
In a star schema, what is the main advantage of using surrogate keys in fact tables?
Which analytics type is focused on predicting future outcomes?
What is the result of SELECT COALESCE(NULL, NULL, 5, 10);?
Which SQL clause is used to summarize data?
Which OLAP operation allows drilling down into more detailed data?
Which OLAP operation summarizes data along a dimension?
