The room is rectangular with an area of 6*6*80=2880 square decimeters.

The area of a square brick with a side length of 8 decimeters is 8*8=64 square decimeters.

Then 2880 divided by 64=45 bricks.

the second question

Note that the railway has two tracks!

240 divided by 2 and multiplied by 6m=720m (this is the total length of the railway).

So 720 divided by 9 times 2= 160 new track.