Question

A rectangular floor which measures 15 m*8 m is to be laid with tiles measuring 50 cm * 25 cm . Find the no. of tiles required. Further if a carpet is laid on the floor  so that a space of 1 m exist between its edges and the edges of the floor , What fraction of the floor is uncovered?

Answer 1

No of tiles used = area of floor / area of each tile = 15*8*100*100/50*25=960 tiles

Answer 2

Consider ABCD as a rectangular field of measurement 15m × 8m

Length = 15 m

Breadth = 8 m

Here the area = l × b = 15 × 8 = 120 m2

Measurement of tiles = 50 cm × 25 cm

Length = 50 cm = 50/100 = ½ m

Breadth = 25 cm = 25/100 = ¼ m

So the area of one tile = ½ × ¼ = 1/8 m2

No. of required tiles = Area of rectangular field/Area of one tile

Substituting the values

= 120/ (1/8)

By further calculation

= (120 × 8)/ 1

= 960 tiles

Length of carpet = 15 – 1 – 1

= 15 – 2

= 13 m

Breadth of carpet = 8 – 1 – 1

= 8 – 2

= 6 m

Area of carpet = l × b

= 13 × 6

= 78 m2

We know that

Area of floor which is uncovered by carpet = Area of floor – Area of carpet

Substituting the values

= 120 – 78

= 42 m2

Fraction = Area of floor which is uncovered by carpet/ Area of floor

Substituting the values

= 42/120

= 7/20

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