Question

a floor measuring 2 metre by 1.5 m is to be covered with tiles measuring 25 CM by 25 cm find the number of tiles required to cover the floor and cost of tiles at rupees 420 per dozen

Answer 1

No. of tiles required =Area of the floor/area of each tile
=(2*100*1.5*100)/(25*25)
=48
Cost of tiles =no. of tiles*rate
=48*(420/12)
=1680₹

Answer 2

Area of floor = 2m * 1.5m = 3$m^{2}$ = 30000$cm^{2}$
Area of tile = 25cm * 25cm = 625$cm^{2}$

Number of tiles required = Area of floor / Area of 1 tile

= 30000cm2 / 625cm2 
=48 tiles = 4 dozens of tiles

Cost per dozen = 420
 Total amount of money required = 4 * 420 = Rs. 1680