Start learning 50% faster. Sign in now
Let the speed of the boat in still water be B km/h and the speed of the stream be S km/h. From the given data: Upstream speed = B - S = 45 km / 6 hours = 7.5 km/h. Downstream speed = B + S = 60 km / 4 hours = 15 km/h. Solving these two equations: B - S = 7.5 and B + S = 15. Adding the two, 2B = 22.5 → B = 11.25 km/h. Substituting B = 11.25 into B + S = 15: S = 3.75 km/h. Now, the speed of the current is doubled, so the new speed of the stream is 2 * 3.75 = 7.5 km/h. The new downstream speed = 11.25 + 7.5 = 18.75 km/h. Time to travel 90 km downstream = 90 / 18.75 ≈ 4.8 hours.
Oil and water can form a stable dispersion with the help of a substance commonly called a(n):
The green colour of the leaves is due to-
Which acid is majorly found in Orange?
Identify the pairing that is not correctly matched.
(I) Dry ice - Solid form of carbon dioxide
(II) Fullerene - An allotrope of hydr...
Which of the following is a non-metal?
Which of the following statements about colloids is NOT true?
Protons were discovered by
Identify the acid commonly used for glass etching.
The substance that is added to make natural rubber strong and more bouncy is-
What is the pH value of a solution that is neither acidic nor basic?