Answer:
1.47 s
Explanation:
From the question,
s = 2d/t................... Equation 1
s = speed of sound in air, d = distance between the boy and the hill, t = time to hear the echo.
make t the subject of the equation
t = 2d/s............... Equation 2
Given: d = 250 meters
Constant: s = 340 m/s
Substitute these values into equation 2
t = (2×250)/340
t = 500/340
t = 1.47 s
