A boat crew row a boat 24 km downstream in 3 hours and tracks the identical loop back upstream in 6 hours. Find the baseline speed of the boat in still water. MCQ with Answer and Explanation
A boat crew row a boat 24 km downstream in 3 hours and tracks the identical loop back upstream in 6 hours. Find the baseline speed of the boat in still water.
A. 7 km/h
B. 5 km/h
C. 6 km/h
D. 8 km/h
Answer: Option C
Solution (By JKSSB Mock Tests)
Downstream tracking speed = 24 / 3 = 8 km/h. Upstream tracking speed = 24 / 6 = 4 km/h. Speed in still water = (8 + 4) / 2 = 12 / 2 = 6 km/h.
In a 1000-meter race, sprinter A beats sprinter B by 100 meters, and sprinter B beats sprinter C by 50 meters. By how many meters does X beat Z in the same race? (Assume consistent speeds)
Explanation:
When A covers 1000m, B covers 900m. When B covers 1000m, C covers 950m. When B covers 900m, C covers 950 * (900/1000) = 855m. Therefore, A beats C by 1000 - 855 = 145 meters.
A boat goes 6 km upstream and returns back to the starting point in 2 hours. If the speed of the stream is 4 km/h, find the speed of the boat in still water.
Explanation:
Let speed of boat in still water be v. 6 / (v - 4) + 6 / (v + 4) = 2 => 3 / (v - 4) + 3 / (v + 4) = 1 => 3(v + 4 + v - 4) = v^2 - 16 => 6v = v^2 - 16 => v^2 - 6v - 16 = 0. Solving the quadratic equation gives (v - 8)(v + 2) = 0. Since speed must be positive, v = 8 km/h.
No comments yet. Be the first to start the discussion!