Question
A cyclist rode for 4 hours at a constant speed of 'x' km/h
and then for 6 hours at a speed of (x - 10) km/h. If his average speed during the entire journey was 35 km/h, what is the value of 'x'?Solution
ATQ,
Distance covered in 4 hours = 4 × x = 4x km
Distance covered in 6 hours = 6 × (x - 10) = (6x - 60) km
Since, average speed = total distance ÷ total time
So, (4x + 6x - 60) ÷ (4 + 6) = 35
Or, 10x - 60 = 350
So, x = (350 + 60) ÷ 10
Or, x = 410 ÷ 10 = 41
A boat goes 52 km in upstream in 4 hours and takes 3 hours to complete a distance of 21 km in downstream. Find the speed of boat in still water.
A submarine can travel a certain distance downstream in 4 hours and the same distance upstream in 8 hours. If the submarine's speed in still water is 12...
Speed of a boat in still water to speed of boat in upstream is 7:5. If the boat can travel 360 km in downstream in 5 hours, then find the time taken by ...
The speed of current is 8 km/h. What will be the respective downstream speed and upstream speed of a boy rowing a boat, if one fifth of the distance cov...
Find the total distance covered by boat in each upstream and downstream in 5 hours if the speed of boat in still water and speed of current is 25 km/h a...
A boat can cover 140 km in downstream in 14 hours and 96 km in upstream in 12 hours. Find the distance travelled by the boat in still water in 5 hours.
The speed of a boat in still water is 35 km/hr. If the boat covers 150 km in upstream in 5 hours, then find the time taken by the boat to travel 200 km ...
A boat goes 60 km upstream in 4 hours and 50 km downstream in 2 hours, then the speed of the boat in still water is
The speed of a boat in still water and the speed of the stream are in the ratio 7:2. If the boat takes 12 hours to travel 240 km upstream, how long will...
A boat’s speed against the stream is 66.67% less than its speed in still water. If it covers 180 km downstream in 4 hours, find the time (in minutes) ...
Relevant for Exams:
