Solve the following:
When wooden planks are piled, the total thickness of the pile is 38.7 cm. If the thickness of each plank is 0.9cm, how many planks are there in the pile?
How many bricks, each of size 25 cm×13.5 cm×6 cm will be required to build a wall 8 m long, 5.4 m high and 33 cm thick?
How many bricks of 25cm by 20cm by 12cm are required to build a wall 3m long, 3m high and 30cm thick?