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_(2)+t_(2)))`
C. `v(t_(1)+t_(2))`
D. `(v(t_(1)+t_(2)))/(2)`

Answer

D

Explanation

For first echo `2d_(1)=vt_(1)`
For second echo `2d_(2)=vt_(2)`
`:.d=d_(1)+d_(2)=(v(t_(1)+t_(2)))/(2)`