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Hugo de Vries was a Dutch botanist who, at the turn of the 20th century, rediscovered Mendel's laws of genetics and introduced the concept of mutations. He is credited with the discovery of mutation based on his observations of the evening primrose plant.
If the sum of upstream and downstream speed is 20 km/hr and the speed of the current is 5 km/hr. Then find time taken to cover 45 km in downward?
A boat covers a certain distance upstream in 6 hrs and comes back to starting point with current in 3 hrs, If boat's upstream speed is 15 km/hr, then, f...
The speed of a boat in still water increases by 4 km/hour after each hour. The speed of stream is 3 km/hour. If the boat travelled 60 km in 3 hours in d...
A steamer covers 80 km in 5 hr. in still water. If the speed of the steamer in still water is 50% more than that of the stream, then time is required fo...
A boat takes 12 hours longer to cover 378 km upstream than it does to cover the same distance downstream. The speed of the stream...
A boat can cover 130 km in downstream in 10 hours and 120 km in upstream in 8 hours. Find the speed of boat in still water
A boat travels 30 km upstream and 45 km downstream in 6 hours. If the speed of the stream is 4 km/h and the boat’s speed in still water is 8 km/h, wha...
The time taken by a boat to cover 72 km downstream is 3 hours less than the boat to cover a certain distance in upstream. The dow...
A boat can travel 36 km downstream in 40 min. The ratio of the speed of the boat in still water to the speed of the stream is 5: 4. How much time will t...
The ratio of the speed of the boat in upstream to that of in downstream is 5:9, respectively. If the speed of the current is 7 km/h, then find the speed...