Question

Rahul is constructing his house .He wants to make a Hall of dimensions 20m x 15 m such that it has a border of the black granite 0.5 m wide on all four sides and a black granite circle in the middle of radius 1.5l4 m. Calculate the cost of the granite used at rupees 1200 per square metre. Please give the solution fast.

Answer 1

The area of the wall without granite border- 20×15=300 sq. m

0.5 m of granite border on all four sides of the wall increases both height and width of the wall.

height = 20 + .5 + .5 = 21 m
width becomes 16 m

The new area = 16×21 = 336 sq m

So, the area of the border 336 - 300 = 36 m

The area of the circle is $\pi r^2$

where r is the radius.

The area is 3.14 × 1.514 × 1.514 = 7.2 sq m

Total area of granite = 36 + 7.2 = 43.2 sq m

The cost= 43.2 × 1200 = 51840 INR.

Cost would be रु 51840