13. What will be the cost of gardening 1 metre broad boundary around a rectangular plot having perimeter of 340 metres at the rate of Rs.10 per square metre?
Answer :
2(l+b) = 340
Area of the boundary [(l+2)(b+2)-lb]
=> 2(l+b)+4 = 344
Therefore, Cost of gardening = Rs.(344*10) = Rs.3440
