Question

Upstream speed of a boat is 12 km/hr which is 75% of the speed of boat in still water. Find
how much distance boat will cover in 6 hr in downstream?​

Answer 1

Answer:

120 km

Step-by-step explanation:

let speed of boat in still water be x then

ATQ in upstream speed of boat is 75% of speed of boat In still water i.e

x (75) /100 = 12

3x/4 = 12

x = 4 *4 = 16km/hr

now speed of water = decrease in speed of boat i.e 25 % of x

then speed of water = 16 * 25/100. = 4km/hr

now total spees in downstream

= speed of boat + speed of water

= 16 + 4 = 20km/hr

now, distance = speed*time

= 20 * 6 = 120km

Answer 2

Answer:

So distance covered downstream  in 6 hrs=120 km

Step-by-step explanation:

Let speed of boat in still water=x km/hr

and speed of water =y

Upstream speed=x-y

Given x-y=0.75x=12--------------(1)

x=12/0.75=16 km/hr

So the speed of boat in still water=16 km

from(1)

16-y=12

y=16-12=4 km/hr

Hence

Speed in down stream=(x+y)=16+4=20 km/hr

So distance covered in 6 hrs=20*6=120 km