Question
Which functional dependency does not holds in given
relation and why? Read the below passage and answer the questions Functional dependency A B means that B is dependent on A i.e. from the value of A we can find the value of B from the relation. Therefore, to prove A B holds in a relation, one of the following conditions must be true: Condition1: either all the value of A must be unique Or Condition2: all the value of B must be same Or Condition3: If two or more tuples/rows of the relation have same value for attribute A then there must be also same value for attribute B i.e. if t1[A] = t2[A] then there must be t1[B] = t2[B].Solution
v->wx satisfies condition 3 i.e. value of v is repeated 3 times ( 7 ) then value of wx is also repeated . so option 1 is correct. yz->x satisfies condition 2, i.e. all values of x are same, so option 2 is correct. x ->yz does not satisfy any of the three conditions, so option 3 is incorrect.
- A dog sees a rabbit 75 meters away and begins chasing it. The rabbit runs at 14 m/sec, while the dog runs at 20 m/sec. How much time will it take for the d...
A man walks at 5 km/h for 2 hours and then at 4 km/h for 1.5 hours. Find the total distance covered and his average speed for the whole journey.
A Bus moving at a speed of 's' km/h can pass a stationary person in 16 seconds and a tunnel Bridge that is 240 meters long in 28 seconds. Determine the ...
Two cyclists are riding towards one another at speeds of 36 km/h and 27 km/h. What will be the distance between them 5 seconds before they meet?
- Amit covers a journey in 12 hours at a constant speed of 18 km/h. At what speed should he travel to cover the same distance in just 9 hours?
A policeman saw a thief from a distance of 450 m. When the policeman started chasing him, the thief also started running. The ratio of speeds of the th...
A reporter gets Rs. 40 per km for taxi travel and Rs. 20 per km for auto travel. In one week, he travelled 120 km and claimed Rs. 3600. How many km did ...
A thief is spotted by a policeman from a distance of 200 meters. When the policeman starts the chase, the thief also starts running. If the speed of the...
A motor-cycle covers 90 km with a speed of 40 km/hr. find the speed of the motor-cycle for the next 90 km journey so that the average speed of the whole...
- Vikram drives for 15 hours at a speed of 22 km/h. If he wants to travel the same distance in 11 hours, what speed should he maintain?