A person standing between two parallel hills fires a gun and hears the first echo after `t_(1)` sec and the second echo after `t_(2)` sec. The distance between the two hills is

Options

A. `(v(t_(1)-t_(2)))/(2)`
B. `(v(t_(1)t_(2)))/(2(t_(1)+t_(2)))`
C. `v(t_(1)+t_(2))`
D. `(v)/(2)(t_(1)+t_(2))`

Answer

D

Explanation

Distance b/w man and hill 1, `d_(1)= (vt_(1))(2)`
Distance b/w man and hill 2, `d_(2)= (vt_(2))(2)`
Distance b/w the two hills, `d = d_(1)+ d_(2)`
`d= (v(t_(1)+t_(2)))/(2)`