Answer:
The bottom of the boat is submerged 0.07m
Step-by-step explanation:
For this problem you should take in consideration the Archimedes´ principle, that states that the volume of a submerged object is equal to the volume of the displaced water.
In this case the problem gives you the information about length and width and also says that is a flat-bottomed boat, so you can calculate the volume as:

where the height is the depth that is the boat submerged, and is the information that we need to find, so

solving for V:

replacing the volume in terms of its measures:

solving for the height:

Finally you should replace the values:



As we said before, this is the height at which the boat is submerged.