Find the number of tiles, 20 cm x 14 cm x 6 cm, required to construct a wall 20 m long, 10 m high and 70 cm thick. If 10% of the wall is filled with mortar.
A string is 148 cm long. It is cut into 3 pieces. The longest piece is 4 times as long as the middle sized piece and the shortest piece is 77 cm shorter than the longest piece. Find the length of the shortest piece (in cm).
A rope is 89 cm long. It is cut into 3 pieces. The longest piece is 3 times as long as the middle-sized piece and the shortest piece is 44 cm shorter than the longest piece. Find the length of the shortest piece (in cm).
