Question

A door of length 10m and breadth Im is fitted in a wall. The length of the wall is 4.5 m and the breadth is 90m(Fig11.6) Find the cost of white washing the wall, if the rate of white washing the wall is * 50per m​​​

Answer 1

Answer:

Area of rectangular door=length×breadth=2m×1m=2m

2

Area of wall including door=length×breadth=4.5m×3.6m=16.2m

2

Now, Area of wall excluding door

=Area of wall including door−Area of door

=16.2−2=14.2m

2

Since, The rate of white washing of 1m

2

the wall=Rs. 20

Therefore, the rate of white washing of 14.2m

2

the wall=20×14.2

=Rs. 284

Thus, the cost of white washing the wall excluding the door is Rs. 284.

Answer 2

Answer:

Tip:- We have apply Area of Rectangle, A= Length × Breadth.

Step:- Area of door having length 10 mt. And breadth 1 mt is = 10×1= 10 sq. mt.

Area of wall having length 4.5 mt. And breadth 90 mt is = 4.5×90 = 405 sq. mt

Now, Area of wall excluding the door is = (405-10) = 395 sq.mt

The cost of white washing the wall with ₹50 per mt. Is = 50×395 = ₹19, 750