• Numerical Ability - Mensuration
Question

The perimeter of a rectangular plot is 210 m. Find the cost of gardening 2 m broad boundary around rectangular plot whose perimeter The cost of gardening is Rs 14 per m2

  • A) Rs 6450
  • B) Rs 6400
  • C) Rs 6480
  • D) Rs 6104
  • E) Rs 6880
Solution

D) Rs 6104
Explanation: 

Given 2(l+b) = 210
2 m broad boundary means increase in l and b by 4 m
So area of the boundary will be [(l+4)(b+4) – lb] = 4(l+b) + 16 = 2*[2(l+b)] + 16 = 2*210 + 16 = 436 m2
So cost of gardening = 436*14

D) Rs 6104
Explanation: 

Given 2(l+b) = 210
2 m broad boundary means increase in l and b by 4 m
So area of the boundary will be [(l+4)(b+4) – lb] = 4(l+b) + 16 = 2*[2(l+b)] + 16 = 2*210 + 16 = 436 m2
So cost of gardening = 436*14

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