A motor boat heads upstream a distance of 24km on a river whose current is running at 3Km
per hour. The trip up and back takes 6 hours. Assuming that the motor boat maintained a
constant speed, what was its speed?
Answers
Answer:
Heya user........... ❤
Let the speed of the boat in still water be x km/h
Hence, speed of boat in upstream =( x-3) km/hr
& in downstream = (x+3) km/hr
That’s why,
24/ (x+3) +24/(x-3) = 6
=> 48x = 6 (x^2 -9)
=> x^2 - 8x -9 = 0
=> (x-9) (x+1) =0
Therefore, x= 9, -1
Note: x can't be negative.
So, speed of boat = 9 km/hr
Hope it’s helpful..... ☺
Answer:
x is 9 kmph
Step-by-step explanation:
let speed of the boat be x kmph
then given,
total distance covered=24km
speed of current =3 kmph
total time taken for the trip=6 hrs
speed of boat in upstream is x-3 kmph
speed of boat in down stream =x+3 kmph
speed =distance/time ,time=distance/speed
24/x-3 +24/x+3 = 6 ->(1)
(24(x+3)+24(x-3))/x^2-9= 6
48x=6x^2-54
6x^2-48x-54=0
x^2-8x-9=0
(x-9)(x+1)=0 so x is 9 kmph or -1 kmph but -1 kmph is not considered so answer is 9 kmph
verification:-
put x is 9 is equation 1
24/6. +24/12= 4+2 is 6