Question
Jack is twice efficient as Jill and Jill can do a piece
of work in 30 days. Jill started the work and after a few days Jack joined him. They completed the work in 22 days. From the starting, for how many days they worked together?Solution
Jill Jack Efficiency 1 : 2 Jill can do this job in 30 days so let total work = 1×30 = 30 units So let Jill work alone for x days and they work together for remaining i,e. (22-x) Hence 1×x+3(22-x) = 30 x +66 - 3x = 30 36 = 2x So x = 18 days So they work togethr for (22-x) i.e . 4 days
A coach sees an athlete 85 meters ahead on the track and begins running after him. The athlete is running at a speed of 19 m/sec, while the coach runs a...
A person 'X' covered a distance of 'd+40' kilometers at a speed of 40 km/h, another distance of 'd' kilometers at a speed of 15 km/h, and a third distan...
- A delivery boy travels a certain distance from his warehouse to the customer’s house. At a speed of 15 km/h, he arrives 18 minutes late. But when riding ...
- A spy is 1.8 km ahead of an agent who begins to chase him. The agent runs at a speed of 12 m/s, while the spy runs at 8 m/s. How much time will the agent t...
A car covers its journey at the speed of 80 km/hr in 10 hours. If the same distance is to be covered in 4 hours, by how much the speed of the car will h...
As observed from the top of a light house, 120 √3 m above the sea level, the angle of depression of a ship sailing towards it changes from 30°...
A car travels at 60 km/h for 1 hour, 45 km/h for 2 hours, and 90 km/h for 1 hour. Find its average speed.
A car travels from town A to town B at 40 km/h and returns from B to A at 50 km/h. If the distance between A and B is 100 km, find the average speed for...
Armaan is traveling at a speed of 40 km/h, and it takes him 90 minutes to reach his office. However, after completing half of the journey, Armaan took a...
A man is travelling at a speed of 20 km/h such that he will take 60 minutes to reach his destination. But after completing half the journey, the man too...
Relevant for Exams:
