question_answer

What would be the cost of preparing a 10m wide garden around a circular field with diameter equal to 220 metres, if the cost of preparing the garden is Rs. 21 per sq metre?

A)  Rs. 151800                  

B)  Rs. 151852      

C)         Rs. 141720      

D)  Rs. 150500

E)  None of these

Correct Answer: A

Solution :

\[\therefore \]Area of the garden\[=\pi [{{(120)}^{2}}-{{(110)}^{2}}]\] \[=\frac{22}{7}(14400-12100)\] \[=\frac{22}{7}\times 2300\,\,sq\,\,metres\] Now, required cost \[=\frac{22}{7}\times 2300\times 21=Rs.\,\,151800\]