Question
What biological control agent is considered most
“useful” in managing a wide range of insect pests effectively in agroecosystems?Solution
Parasites of aphids, like parasitoid wasps, are widely effective due to the economic importance of aphids as pests.
The speed of a boat in still water is 6 km/hr more than that of the current. The time taken by the boat to cover 675 km downstream is 13.5 hours. Find t...
- A boat takes the same amount of time to travel (x – 24) km upstream as it takes to cover (2x – 84) km downstream. If the speed of the boat is 12 km/h a...
Ratio of speed of boat in downstream and speed of stream is 7:3, if speed of current is 9 km/hr, then find distance travelled (in km) upstream in 6 hours.
A boat can cover 220 km in downstream in 11 hours and 126 km in upstream in 18 hours. Find the speed of boat in still water
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 7:5:2, respectively. If ...
The speed of the stream is 20 km/h. Boat ‘A’ covers 120 km distance against the stream in 6 hours and boat ‘B’ covers 120 km distance against th...
A motorboat in still water travels at a speed of 36 km/hr. It goes 64 km upstream in 2 hours. The time taken by it to cover the same distance down the s...
A man rows upstream 18 km and downstream 30 km taking 6 hours each. Find the man’s speed in still water.
A boat running downstream covers a distance of 45 km in 9 hrs and covering the same distance upstream in 15 hrs. What is the speed of a boat in still wa...
A boat can travel 72 km upstream and 108 km downstream in 5 hours. Find the speed of the boat in still water if the ratio of the ...
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