Let 1 day work of 1 man = 1 units So total work = 25 ×13 = 325 units Suppose after n days work is finished. So, 1 + 2 + ………… +n = 325 ⇒ (n(n+1))/2 = 325 n² + n – 650 = 0 n² + 26n – 25n – 650 = 0 n(n + 26 ) – 25(n + 26) = 0 (n - 25) (n + 26) ∴ n = 25 Hence, the work will be finished in 25 days.
Two cars, 'A' and 'B,' are heading towards each other on a straight road. Car 'A' is traveling at a speed of 56 km/h, while Car 'B' is moving at 34 km/h...
A boy can swim a certain distance downstream in 5 hours and return in 7 hours. If the rate of stream is 4 kmph then what is the speed of boy in still wa...
A bus takes 10 seconds to pass a standing man and 28 seconds to pass a traffic light, which is 405 meters long. Determine the time it takes for the bus ...
‘A’ and ‘B’ started moving towards each other at same time with a speed of 25 km/hr and 20 km/hr, respectively. If the distance covered by ‘Aâ...
It takes 8 hours less to travel from point 'E' to point 'F' at a speed of 60 km/h than it takes to travel the same distance at 24 km/h. If 30% of the di...
A train 200 m long passes a pole in 10 seconds. How long will it take to pass another train 300 m long running in the opposite direction at a speed of 3...
Train P starts from Lucknow to Dehradun at 11:55 am with an average speed of 27.5 m/s. Train Q starts from Dehradunto Lucknowat 1:35 pm with an average ...
A car running with a speed of 52 km/hr takes 4 hours to go from 'A' to 'B'. If on the way back from 'B' to 'A', the car takes 20% less time than it take...
1200 metres long train crosses a man who is moving in the same direction with a certain speed, in 30 seconds. If the same train can cross a tree in 20 s...
The speed of a car is 60% more than the speed of a bus. The train can cover (d-250) km distance in (t-3.5) hours. The car covers (d+140) km distance in ...
