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Start learning 50% faster. Sign in nowOzone depletion refers to the phenomenon of reductions in the amount of ozone in the stratosphere. The problem of ozone depletion is caused by high levels of chlorine and bromine compounds in the stratosphere. The origins of these compounds are chlorofluorocarbons (CFC), used as cooling substances in air conditioners and refrigerators, or as aerosol propellants, and Bromo fluorocarbons (halons), used in fire extinguishers. As a result of depletion of the ozone layer, more ultraviolet (UV) radiation comes to Earth and causes damage to living organisms. UV radiation seems responsible for skin cancer in humans; it also lowers production of phytoplankton and thus affects other aquatic organisms. It can also influence the growth of terrestrial plants.
A boat goes 60 km upstream in 4 hours and 50 km downstream in 2 hours, then the speed of the boat in still water is
When a speed of stream is 25% of the speed of boat in still water. If the boat can travel 60 km upstream in 5 hours and 80 km downstream in 4 hours, the...
The speed of a boat going upstream is 20% slower than when it is traveling downstream. The boat travels 90 km in still water over a period of 4 hours. C...
A boat goes 52 km in upstream in 4 hours and takes 3 hours to complete a distance of 15 km in downstream. Find the speed of boat in still water.
The ratio of the speed of boat in upstream to speed of boat in downstream is 7:9. If the boat can cover a total of 49 km upstream and 81 km downstream i...
If a man rows at the rate of 17 kmph in still water and his rate against the current is 7 kmph, then find the man’s speed with downstream...
The ratio of the speed of boat ‘A’ in still water, the speed of boat ‘B’ in still water and the speed of the current is 11:5:2, respectively. If...
The speed of current is 30 km/hr. If the speed of the boat in still water had been 13 km/hr more than the original speed then it would take 7.5 hours to...