Question
A boat takes a total of 6 hours to travel 45 km downstream
and 30 km upstream. In another scenario, the same boat takes 8 hours to cover 60 km upstream and 30 km downstream. Determine the speed of the stream (in km/h).Solution
Let the upstream and downstream speed of boat be 'U' km/h and 'D' km/h respectively.
So, (45/D) + (30/U) = 6 --------- (I)
And, (30/D) + (60/U) = 8 -------- (II)
On solving 2 X equation I - equation II,
We get, 2 X [(45/D) + (30/U) ] - [(30/D) + (60/U) ] = 2 X 6 - 8
Or, (90/D) + (60/U) - (30/D) - (60/U) = 12 - 8
Or, (60/D) = 4
Or, 'D' = 15
On putting value of 'D' in equation I,
We get, (45/15) + (30/U) = 6
Or, 3 + (30/U) = 6
Or, (30/U) = 3
Or, 'U' = 10
Speed of stream = (1/2) X (downstream speed - upstream speed)
= (1/2) x (15 - 10) = 2.5 km/h
Sew village concept facilitates the empowerment of Agriculture farmers
Hamulate type of wing coupling apparatus found in ____
What is the application efficiency in Furrow irrigation method?
Apatite is a group of minerals which mainly contains___
A crossing of two or more breeds and alternately mating the hybrid females over several generations with males of the original breeds is called
Domination of weed causes:
Which order of insects undergoes all four stages of metamorphosis?
Severe drought occurs when deficiency of rainfall is above :
The scientific name of grass carp is…………………………..
Important grassy weed of transplanted rice is: