Question
The boat's speed in still water
is 20% greater than the speed of the stream. If it takes the boat 4 hours more to travel 176 km downstream than it does to travel 8 km upstream, what is the time required for the boat to travel 264 km downstream and 16 km upstream?Solution
ATQ, Let the speed of the stream be 'a' km/hr Therefore, speed of the boat in still water = 1.20 × a = '1.2a' km/hr Downstream speed of the boat = 1.2a + a = '2.2a' km/hr Upstream speed of the boat = 1.2a - a = '0.2a' km/hr According to the question, (176/2.2a) - (8/0.2a) = 4 Or, (80/a) - (40/a) = 4 Or, 4a = 40 Or, 'a' = (40/4) = 10 Therefore, downstream speed of the boat = 2.2a = 2.2 × 10 = 22 km/hr Upstream speed of the boat = 0.2a = 0.2 × 10 = 2 km/hr Required time taken = (264/22) + (16/2) = 12 + 8 = 20 hours
Which of the following is arranged in order of decreasing conductivity?
_____ is used for making chemical apparatus like beakers, flasks, etc.
What is the simplest hydrocarbon?
Statement I: Glass is not considered as a true compound. Statement II: Glass does not have a definite melting point.
Codes:
Turquoise is an ore/mineral of:
_____ is the movement of chemicals in the upper layers of soil into lower layers or into groundwater by being dissolved in water.
What happens to the boiling point of water at higher altitudes?
The colour of neutral litmus solution is
Which endocrine gland requires iodine to synthesize a particular hormone, whose deficiency may cause goitre disease?
Which is used to treat indigestion?
