Question
Biological Oxygen Demand (BOD) is a measure
of:Solution
BOD finds its primary importance in sewage treatment plants. It gives the respiration rate of sewage, sludge, soil, and garbage . It determines the rate of respiration in living beings. Measuring BOD gives the COD or Chemical Oxygen Demand of inorganic substances.
- A train with a length of 230 metres, moving at a speed of 48 km/h, takes 50 seconds to cross a platform. Find the platform's length.
Length of a train is double the length of a platform. If the train crosses the platform in 72 seconds, then find the time taken by train to cross a pole.
- Train 'R' can cross a pole in 6 seconds and a 240 metres long bridge in 10 seconds. Train 'S' whose length is 75% of the length of train 'R' runs in the sa...
Two trains 160 metres and 140 metres in length are running towards each other on parallel tracks, one at the rate 52 km/hr and another at 38 km/hr. In h...
- Train 'A' can cross a tree and a bridge of 300 metres in 5 sec and 15 sec, respectively. Train 'B' can cross the same bridge in 20 seIf the length of train...
A train running with a speed of 99 km/hr can cross a pole in 13 seconds and a platform in 17 seconds. Find the length of the platform.
- Train 'X' can cross a pole in 15 seconds and a 180 metres long bridge in 18 seconds. Train 'Y' whose length is 80% of the length of train 'X' runs in the s...
 A train of length 220 m crosses a platform of length 330 m in 22 seconds. Speed of the train is:
A goods train leaves a station at a certain time and at a fixed speed. After 10 hours, an express train leaves the same station and moves in the same di...
800 metres long train crosses a man who is moving in the same direction with a certain speed, in 40 seconds. If the same train can cross a tree in 20 se...
