Question
Two pipes X and Z can fill a tank in 36 hours and 48 hours
respectively, while pipe Y can drain the tank in 72 hours. If pipes X and Z are opened together for 10 hours and then Z is closed and Y is opened, how long will it take to completely fill the tank?Solution
ATQ,
Let capacity of the tank = 288 litres (LCM of 36, 48, and 72)
Water filled by pipe X in 1 hour = 288 / 36 = 8 litres
Water filled by pipe Z in 1 hour = 288 / 48 = 6 litres
Water drained by pipe Y in 1 hour = 288 / 72 = 4 litres
In first 10 hours, X and Z together fill:
= 10 × (8 + 6) = 10 × 14 = 140 litres
Remaining volume to be filled = 288 – 140 = 148 litres
Now only pipes X and Y are open, so effective rate = 8 – 4 = 4 litres/hour
Time to fill remaining tank = 148 / 4 = 37 hours
Total time taken = 10 + 37 = 47 hours
A train covers a certain distance at a speed of 36 km/h and the next same distance with a speed of 45 km/h and the next same distance with a speed of 60...
The radius of a circular garden is 42 m. The distance (in m) covered by running 8 rounds around it, is: (Take )
- Sita takes 6 hours to walk from village 'D' to village 'E' at a speed of 5 km/h. Then she increases her speed by 60% and takes 2 hours to reach village 'F'...
Vehicles K and L move at speeds of 20 km/hr and 35 km/hr respectively. If K travels 45 km less than L during the same time, what is the distance covered...
A man travels some distance at a speed of 12 km/hr and returns at a speed of 9 km/hr. If the total time taken by him is 4 hrs 40 min, the distance is
Two trains start at the same time from A and B and move towards each other at the rates of 10km/h and 27 km/h, respectively. When they meet, it is found...
A train travels from station ‘P’ to station ‘Q’ at a constant speed. If its speed was increased by 20 km/h, it would have taken 1 hour less to c...
A car completes a journey in 6 hrs with a speed of 50 km/hr. At what speed must it travel to complete the journey in 5 hrs?
Train A's speed is 25% less than that of Train B, and its length is half the length of Train B. Train A crosses a 400 m bridge in 36 seconds, while Trai...
A bus covers 216 km in 3 hours. The bike’s speed is 6 m/s less than the bus. How far (in metres) does the bike travel in 4 minutes 15 seconds?
Relevant for Exams:
