Asked by sangita
A boat takes 90 minutes less to travel 36 km downstream then to travel the same distance upstream.If the speed of the boat in still water is 10 kmph.What is the speed of the current?
Answers
Answered by
Steve
since time = distance/speed,
36/(10+x) = 36/(10-x) - 3/2
x = 2
check:
36/12 = 3
36/8 = 4.5
ok
36/(10+x) = 36/(10-x) - 3/2
x = 2
check:
36/12 = 3
36/8 = 4.5
ok
Answered by
sangita
I don't understand the solve.please explain it.
Answered by
Steve
If the current's speed is x, then
10+x is the downstream speed of the boat
10-x is the upstream speed.
the downstream time is 90 minutes (3/2 hours) less than the upstream time. Hence, the given equation.
36/(10+x) = 36/(10-x) - 3/2
36(10-x) = 36(10+x) - 3/2 (10-x)(10+x)
now just expand the factors and collect terms to get
x^2 + 48x - 100 = 0
(x+50)(x-2) = 0
10+x is the downstream speed of the boat
10-x is the upstream speed.
the downstream time is 90 minutes (3/2 hours) less than the upstream time. Hence, the given equation.
36/(10+x) = 36/(10-x) - 3/2
36(10-x) = 36(10+x) - 3/2 (10-x)(10+x)
now just expand the factors and collect terms to get
x^2 + 48x - 100 = 0
(x+50)(x-2) = 0
Answered by
Aruna
Couldnt get thr ans sir pls solve it..
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.