How many tiles whose length and breadth are 12 cm and 5 cm respectively will be needed to fit in a rectangular region whose length and breadth are respectively:
(a) 100 cm and 144 cm
(b) 70 cm and 36 cm
(a) We know that,
Area of rectangle = Length × Breadth
It is given in the question that,
Length = 100 cm
Breadth = 144 cm
Therefore,
Area = Length × Breadth
= 100 × 144
= 14400 cm2
Therefore,
Area of one tile = 12 × 5
= 60 cm2
Hence,
Number of tiles required = 
= 240
Therefore, total 240 tiles are required
(b) We know that,
Area of rectangle = Length × Breadth
It is given in the question that,
Length = 100 cm
Breadth = 144 cm
Therefore,
Area = Length × Breadth
= 70 × 36
= 2520 cm2
Area of one tile = 60 cm2
Hence,
Number of tiles required = 
= 42
Therefore, total 42 tiles are required