The first cliff’s distance from the guy,
2\(\times \)D1 = velocity\(\times \)time
D1 = (320 \(\times \)4) / 2
D1 is equal to 640 metres.
D2 = (320 \(\times \) 6) / 2 is the distance between the second cliff and the person.
D2 = 960 metres
D1 + D2 = distance between cliffs
= 640 + 960
= 1600 m