A motorboat whose speed is 18 kilometre per hour in still water takes 1 hour more to go 24 km upstream then to return downstream
Answers
we have to find the speed of the stream...
let the speed of the motorboat = x
so,
the speed of the boat upstream = 18-x
the speed of the boat downstream = 18+x
now,
time to go upstream (t1) = D/S = 24/18-x
time to go downstream (t2) = D/S = 24/18+x
ATQ,
t1-t2 = 24/18-x - 24/18+x
24(18+x) - 24(18-x) = (18-x) + (18+x)
x2+48x-324 = 0
by middle term splitting
x2+54x-6x-324 =0
x(x+54)-6(x-54) =0
(x-6) (x+54) =0
x-6 = 0 and x+54 = 0
x = 6 and x = -54
hope it's helps you..
plz mark as a brainlist...
Let the speed of the stream be x km\hr.
The speed of the boat upstream = (18 - x) km/hr
The speed of the boat downstream = (18 + x) km/hr
Distance = 24 km
As given in the question,
Time for upstream = 1 + Time for downstream
24/(18 - x) = 1 + 24/(18 + x)
24/(18 - x) - 24/(18 + x) = 1
x2 + 48x - 324 = 0
(x + 54)(x - 6) = 0
x ≠ - 54 as speed cannot be negative.
x = 6
The speed of the stream = 6 km/hr.