According to the question: For A: Speed of boat = 18 km/h Speed of stream = 7 km/h Speed in upstream = 18 - 7 = 11 km/h Speed in downstream = 18 + 7 = 25 km/h Total time = 180/11 + 270/25 ≈ 16.36 + 10.8 ≈ 27.16 hours So, A can't be the answer. For B: Speed of boat = 18 km/h Speed of stream = 9 km/h Speed in upstream = 18 - 9 = 9 km/h Speed in downstream = 18 + 9 = 27 km/h Total time = 180/9 + 270/27 = 20 + 10 = 30 hours So, B can be the answer. For C: Speed of boat = 18 km/h Speed of stream = 5 km/h Speed in upstream = 18 - 5 = 13 km/h Speed in downstream = 18 + 5 = 23 km/h Total time = 180/13 + 270/23 ≈ 13.85 + 11.74 ≈ 25.59 hours So, C can't be the answer. For D: Speed of boat = 18 km/h Speed of stream = 10 km/h Speed in upstream = 18 - 10 = 8 km/h Speed in downstream = 18 + 10 = 28 km/h Total time = 180/8 + 270/28 = 22.5 + 9.64 ≈ 32.14 hours So, D can't be the answer.
Which of the following is true about the immature scale insects?
Which pest is identified by the ‘honeydew’ it secretes, which often leads to the development of sooty mold on plant leaves ?
Apis mellifera is also known as
___________signifies the separation between the old exocuticle and the epidermis, creating a narrow space that aids in the molting process.
Drones are
Pebrine disease of silkworm is caused by
The type of glands associated with the insect's head appendages is primarily responsible for silk production in certain insect larvae is
Which of the following are the characteristic features of an Insect?
Which silkworm feedw on castor tree
The total number of abdominal legs in the larval stage of the mustard sawfly is ____.
