Question

The boys of class 8 decided to collect money and rebuild the wall of a poor man's home which was destroyed in a flood.How many bricks will be required to build a wall 15m long , 20cm thick , 2m high , a brick being 20cm long , 10cm wide and 7.5cm thick? If the cost of the brick is Rs. 2.25 , what is the total amount that they must collect?

Answer 1

I think it's RS. 9,00,000

Answer 2

given, dimensions of wall:-

length = 15m. = 1500 cm

breadth = 20cm

height = 2m. = 200 cm

volume of wall = l*b*h

                       =  1500 * 20 * 200

                          = 6000000 cubic cm

given, dimensions of a brick :-

length = 20 cm

breadth = 10 cm

height = 7.5 cm

volume of 1 brick = l * b * h

                            = 20 * 10 * 7.5

                           = 1500 cubic cm.

no. of bricks = volume of wall / volume of 1 brick

                      = 6000000 / 1500

                      = 4000 bricks

now cost of 1 brick = Rs. 2.25

∴ cost of 4000 bricks = 4000 * 2.25

                                 = Rs. 9000---------------------Ans.