Question
Speed of a boat in still water is three times the speed
of the boat in upstream. If the boat takes 48 minutes to cover 24 km in downstream, then find the speed of the boat in still water.Solution
Let speed of the boat in still water be ‘3x’ km/h. Speed of the boat in upstream = 3x ÷ 3 = ‘x’ km/h Speed of the stream = 3x – x = ‘2x’ km/h Speed of the boat in downstream = 3x + 2x = ‘5x’ km/h ATQ; (24/48) × 60 = 30 So, 5x = 30 Or, x = 6 So, speed of the boat in still water = 3 × 6 = 18 km/h
The speed of a train is 72 km/hr and it takes 12 seconds to cross a man. Find the time taken by train to cross a platform if the ratio of the length of ...
A boy goes to school at 9 km/Hr and return at a speed of 8 km/hr. If he takes 17 hrs in all. Find the distance from his village to school?
The speed of the cycle changes with the change in speed of wind. Time taken by cycle to travel 20 km., is 2 hours when wind is in the direction of the c...
A train 180 meters long is moving at a speed of 72 km/h. How long will it take to cross a platform 120 meters long?
In a 250-metre race, ‘A’ beats ‘B’ by 16 seconds or 80 metres. Find the time taken by ‘B’ to finish the race.
A man running with the speed of 65 km/hr covers a certain distance in ‘x’ hours. If the same distance can be travelled with a speed of 70 km/h in (x...
- In a 250 metres race, 'K' beats 'M' by 50 metres, and 'M' beats 'L' by 20 metres. By how many metres does 'K' beat 'L'?
If the diameter of a sphere is 42 cm, find the total surface area of the sphere.
Ajay and Vishal left the place ‘X’ with different speeds which are in the ratio 4:3 respectively. Ajay left the place 36 seconds after Vishal. If af...
- A person completes a journey in 300 minutes by train at a speed of 60 km/h. What should be his speed by bus to cover the same distance in 7 hours?
