A motorboat travelling at some speed can cover 24 km upstream and 40 km downstream in 17 hours. At the same speed, it can travel 32 km downstream and 12 km upstream in 10 hours. The speed of the stream is:
3 km/h
Let the speed of the boat in still water be b km/h and the speed of the stream be s km/h.
Given equations:
(24 / (b - s)) + (40 / (b + s)) = 17
(12 / (b - s)) + (32 / (b + s)) = 10
Step 1: Express in simpler terms
Dividing the first equation by 2:
(12 / (b - s)) + (20 / (b + s)) = 8.5
Step 2: Subtract the second equation
Subtracting:
12 / (b + s) = 1.5
Solving for b + s:
b + s = 8
Step 3: Solve for s
s = 3 km/h
Final Answer: 3 km/h ✅
Important Questions from Speed, Time & Distance
A thief pursued by a policeman was 150 m ahead at the start. If the ratio of the speed of the policeman to that of the thief was 5:4, then how far (distance in metres) could the thief go before he is caught by the policeman?
A thief pursued by a policeman was 150 m ahead at the start. If the ratio of the speed of the policeman to that of the thief was 5:4, then how far (distance in metres) could the thief go before he is caught by the policeman?
A truck left 30 minutes early than the scheduled time but in order to reach its destination 270 km away in time, it had to slow its usual speed by 6 km/hr. What is the usual speed of the truck?
