SOLUTION: A field 200 m by 150 m has a path of 2m running alonh the perimeter and cross path 3 m wide running in the centre vertically and horizontally. Find the cost of paving the pathways

Algebra ->  Surface-area -> SOLUTION: A field 200 m by 150 m has a path of 2m running alonh the perimeter and cross path 3 m wide running in the centre vertically and horizontally. Find the cost of paving the pathways       Log On


   



Question 1038944: A field 200 m by 150 m has a path of 2m running alonh the perimeter and cross path 3 m wide running in the centre vertically and horizontally. Find the cost of paving the pathways at the rate of rupees 7 per square foot and the cost of sowing the crop in the field at the rate of 5 per rupees square foot?
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
Here is a sketch (not to scale) to visualize the problem:
If I had drawn it two scale, the paths would be too narrow to be visible.
The total area of the field is
%28200m%29%28150m%29=30000m%5E2 .
Part of that (the pathways) needs to be paved, and the rest is where the crop will be planted.
The part where the crop will be planted is represented by the green rectangles.
The (horizontal) length of each of those rectangles is green%28x%29 , and
their (vertical) width is green%28y%29 .
So, in equations system%282m%2Bx%2B3m%2Bx%2B2m=200m%2C%22and%22%2C2m%2By%2B3m%2By%2B2m=150m%29 and in pictures .
2m%2Bx%2B3m%2Bx%2B2m=200m<--->2x%2B7m=200m<--->2x=193m<--->x=193m%2F2<--->x=96.5m, and
2m%2By%2B3m%2By%2B2m=150m<--->2y%2B7m=150m<--->2y=150m-7m<--->2y=143m<--->y=143m%2F2<--->y=71.5m
So surface area of the part for sowing is
4%2896.5m%29%2871.5m%29=27599m%5E2=%28193m%29%28143m%29 = area of the rectangle made by joining the 4 green rectangles.
Since the total area of the field is 30000m%5E2 , the path area to be paved is
30000m%5E2-27599m%5E2=2401m%5E2 .
unfortunately, we have the surface areas in m%5E2 , but the costs for paving and sowing are given per square foot,
but 1m%5E2 is 10.7639squarefeet , so
paving 2401m%5E2 would cost 2401%2A10.7639%2A7rupees=highlight%28180909rupees%29 , and
sowing 27599m%5E2 would cost
27599%2A10.7639%2A5rupees=highlight%281485366rupees%29 .
The total cost of paving and sowing would be
180909rupees%2B1485366rupees=1666275rupees .