Question

Problem - 4.34: Two persons P and Q crosses the river
starting from point A on one side to exactly opposite
point B on the other bank of the river. The person P
crosses the river in the shortest path. The person Q
crosses the river in shortest time and walks back to
point B. Velocity of river is 3 kmph and speed of each
boat is 5 kmph w.r.t river. If the two persons reach the
point B in the same time, then the speed of walk of Q is



please anyone solve it by step by step pls....​

Answer 1

$\pink{ \tt{Answer:}}$

If he swims 6 kmh^-1 .to a inclined to vertical In river plane.

then River is going through 3 kmh^-1

Which makes a obtuse triangle now

if the Result of them is go through the Perpendicular Line to the Horizontal.

then he can swim in the lowest time.

then

6 sin a=3

6 cos a= Result

sin a=0.5

then cos a=(root(3)/2)

so Result is 3 root(3)

now use S=ut

then 2=3root(3)×t

Because of that

t=2/3 root(3) seconds

$\therefore \sf{Use \: Vectors \: as \: Velocities}</p><p></p><p> </p><p>$

Answer 2

Answer:

If he swims 6 kmh^-1 .to a inclined to vertical In river plane.

then River is going through 3 kmh^-1

Which makes a obtuse triangle now

if the Result of them is go through the Perpendicular Line to the Horizontal.

then he can swim in the lowest time.

then

6 sin a=3

6 cos a= Result

sin a=0.5

then cos a=(root(3)/2)

so Result is 3 root(3)

now use S=ut

then 2=3root(3)×t

Because of that

t=2/3 root(3) seconds

\therefore \sf{Use \: Vectors \: as \: Velocities}∴UseVectorsasVelocities