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Let the speeds of boats ‘A’ and ‘B’ in still water be 8x km/hr and 9x km/hr Therefore, speed of the current = 0.25 × 8x = 2x km/hr According to the question, 8x + 2x = 490/7 Or, 10x = 70 Or, x = 7 Therefore, upstream speed of boat ‘B’ = 9x – 2x = 7x = 49 km/hr Downstream speed of boat ‘B’ = 9x + 2x = 11x = 77 km/hr Required time taken = (98/49) + (770/77) = 2 + 10 = 12 hours
Which of the following is true about the immature scale insects?
Which class of pesticides, known for their nerve poison properties and containing compounds like carbaryl, made a significant impact in the 1950s?
Shellac is secreted by
Planting of marigold as trap crop in Tomato and Cotton is used to attract to_______
Which silkworm feedw on castor tree
Kerria sp. is a …. species of lac insect.
Pebrine disease of silkworm is caused by
Trichogramma japonicum is a natural parasitoid which is used to control ________
The scientific name of dammer bee is
Which of the following structures is not the part of the insect’s head capsule?