Question

A rectangular garden 60m×40m has two cement concrete roads each 7m wide, running through its middle, parallel to its breadth and one parallel to its length. What is the cost of constructing the roads at 150 Rupees per metre square​

Answer 1

Let ABCD be the rectangular park.

Let EFGH and IJKL be the two rectangular roads with width 7 m.

Length of the rectangular park, AD = 60 m

Breadth of the rectangular park, CD = 40 m

Area of the rectangular park = Length×Breadth

= 60×40

= 2400 m²

Area of road EFGH = 60×7 = 420 m²

Area of road IJKL = 40×7 = 280 m²

Clearly, area of MNOP is common to both the two roads.

∴ Area of MNOP = 7×7 = 49 m²

Area of the roads,

= Area (EFGH) + Area (IJKL) − Area (MNOP)

= (420 + 280 )− 49

= 651 m²

It is given that the cost of constructing the roads is Rs. 120/m2.

Cost of constructing 651 m² = Rs. (150 × 651) = Rs. 97650