Question

A 80 m by 64 m rectangular lawn has two roads, each 5 m wide, running through its middle, one parallel to its length and the other parallel to its breadth. Find the cost of gravelling the reads at ₹`   40 per    m^2`

Answer 1

The length and breadth of the lawn are 80 m and 64 m, respectively. The layout of the roads is shown in the figure below: 

 

Area of the road ABCD =`80xx5=400m^2` 

Area of the road PQRS=`64xx5=320 m^2` 

Clearly, the area EFGH is common in both the roads  

Area EFGH =`5xx5=25m^2` 

Area of the roads = `400+300-25` 

=` 695m^2` 

Given:

Cost of gravelling `1m^2` area 

Cost of gravelling `695m^2` area =`695xx40` 

=Rs `27,800`