Question

ritu can row downstream 20km in 2hour .and upstream 4km in 2hrs . find her speed of rowing in still water and the speed of current​

Answer 1

Answer:

speed of current =4 km /h

speed of boat =6km/h

hope it helps you thanks

Step-by-step explanation:

x=boat's speed

y= current speed

speed =distance/time

downstream x+y

upstream x-y

x+y=20/2=10

x-y=4/2=2

add 2x=12 x=6

6+y=10 y=10-6=4

so speed of boat and current are 6 and 4 km/h respectively.

Answer 2

Answer:

$\huge{\pink{\boxed{\green{\sf{SPEED\:OF\:STILL\:WATER=6\:km/h}}}}}$

$\huge{\pink{\boxed{\green{\sf{SPEED\:OF\:CURRENT=4\:km/h}}}}}$

Step-by-step explanation:

$\huge{\pink{\boxed{\green{\underline{\red{\sf{SOLUTION-}}}}}}}$

☆ Let the speed of rowing in still water = X km/h

☆ Speed of the current = Y km/h

☆ In downstream relative speed = (X+Y)km/h

☆ In upstream relative speed = (X-Y)km/h

☆ According to given question:

$T=\frac{distance}{speed}\\\to2=\frac{20}{(x+y)}\\\to(x+y)=\frac{20}{2}\\\to(x+y)=10-----(1)\\\\IN\:\:UPSTREAM\\\to T=\frac{d}{s}\\\to2=\frac{4}{(x-y)}\\\to(x-y)=2-----(2)$

☆ Subtracting (1) from (2)

$\to x-y-(x+y)=2-10\\\to x-y-x-y=-8\\\to-2y=-8\\\to y=\frac{-8}{-2}\\{\pink{\boxed{\green{\therefore y=4}}}}$

☆ Putting value of y in (2)

$\to(x-y)=2\\\to x-4=2\\\to x=2+4 \\{\pink{\boxed{\green{\therefore x=6}}}}$