Question

A person standing at A fired a bullet against a wall and hears an echo after 4 s. He walked 170 meters towards the wall and fired another bullet and hears an echo after 2.5 s. What is the distance from the wall to place A?
(A)14O m
(B)240 m
(C)453.3 m
(d)160.66 m

Answer 1

Step-by-step explanation:

[tex]Let the distance from wall to the first fired place be 'd' m.

Then the time after which echo heard is 2 s.

∴V=t2d=22d

V=d               

 He walked 80 m then the distance of person from wall to the second fired place is (d-80)m and time taken for echo to be heard at this point is 1 s.

V=12(d−80)

V=2(d−80)          

From (1) and (2)

d=2d−16)

d=160m

The distance from wall to the second fired place is (d-80) = 160 - 80 = 80 m.

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