Round-trip time determines distances using speed of sound

Steps:

• Depth to sea bed: round-trip time 1.0 s, so depth = (1500 m/s × 1.0 s) / 2 = 750 m.
• Distance to whale: round-trip time 0.6 s, so distance = (1500 m/s × 0.6 s) / 2 = 450 m.
• Whale's height above sea bed: 750 m - 450 m = 300 m.

Why A is correct:

• Matches calculation of depth minus whale distance using round-trip distance formula d = (v × t)/2.

Why the others are wrong:

• B: Assumes one-way time to whale, ignoring round trip.
• C: Equals full round-trip distance to whale, not height above bed.
• D: Equals sea bed depth, not whale position.

Final answer: A