Hello, I'm not sure how to solve this question:

The velocity of a shock wave in water is 1500 m/s, while the velocity of sound in air is 330 m/s. The shock wave from a depth charge just beneath the surface of the water is felt by a ship 5.5 s before the sound is heard by the crew. How far is the ship from the explosion.

How I approach it is like this:

5.5 s delay x 330 m/s = 1815 m (how far the sound travels in 5.5 seconds to reach the ship)

Then I divide 1815 m by 1500 m/s = 1.21 s, meaning it took the shock wave 1.21 s to move the distance the sound travelled in 5.5 seconds, meaning the sound travelled for an additional 1.21 s prior to the 5.5 s delay, since it took the shock wave 1.21 s to first reach the ship.

So this would mean that the sound travelled for 6.71 s to reach the boat, which is 2214.2 m.

The problem is that there is another answer, and I don't know what is wrong with my approach, or what the other approach is, because I'm having trouble conceptualizing this. Any explanations and steps would be much appreciated. Thank you

Edit: oh and the answer given in the text is 2327 m.