The speed of two cyclists are in the ratio 4 : 7. If they cover the same total distance, what is the ratio of the time taken by them? MCQ with Answer and Explanation
The speed of two cyclists are in the ratio 4 : 7. If they cover the same total distance, what is the ratio of the time taken by them?
A. 16 : 49
B. 4 : 7
C. 49 : 16
D. 7 : 4
Answer: Option D
Solution (By JKSSB Mock Tests)
Since time is inversely proportional to speed when distance is constant, the ratio of time taken is the reciprocal of the speed ratio: 1/4 : 1/7 = 7 : 4.
A motorboat covers a certain distance downstream in a river in 3 hours and returns upstream in 4 hours. If the speed of the river current is 3 km/h, find the speed of the motorboat in still water.
Explanation:
Let speed of boat in still water be v. Downstream speed = v + 3, Upstream speed = v - 3. Distance is same, so 3(v + 3) = 4(v - 3) => 3v + 9 = 4v - 12 => v = 21 km/h.
An officer walks to his workplace at 4 km/h and arrives 12 minutes late. If he scales up his speed to 5 km/h, he arrives 6 minutes early. Find the distance to his office.
Explanation:
Distance 1 = 40 * 4 = 160 km. Distance 2 = 60 * 2 = 120 km. Total distance = 280 km. Total time = 6 hours. Average speed = 280 / 6 = 46.66 km/h.
No comments yet. Be the first to start the discussion!