Question

A boatman finds that he can save 6sec in crossing the river by quicker path if the velocity of boat and river be respectivy 17m/s and 8m/s then the river width is

Answer 1

Answer:

The river width is 765 m

Explanation:

Let w be the width of the river.

Now the velocity of the boat is 17m/s

and the velocity of the river is 8 m/s

The time to cross by quickest path with respect to boat is t1 =w/v=d/17

and the time to cross the shortest path, with respect to river is t2=w/√v2−u2

=w/√(17)^2−(8)2

According to the problem  t2−t1=6  sec

w[1/√225−1/17]=6  

or, w[1/15−1/17]=6

or w=6×15×17/2

   =765m.

Answer 2

Answer:

The river width is

Explanation:

765 m..

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