Mensuration Ques 22
Question
Length of the floor of a rectangular auditorium is 6 metre more than the radius of a circle with a circumference of $572 m$. The perimeter of the floor of the rectangular auditorium is $356 m$. What will be cost of flooring the auditorium (only the floor of the auditorium), if the cost of flooring is $ \text{₹} 12 / m^{2}$ ?
(1) ₹ 87,954
(2) ₹ 91,236
(3) ₹ 94,284
(4) ₹ 75,490
(5) None of these
(IBPS RRBs Office Assistant CWE Exam. 09.09.2012)
Show Answer
Correct Answer: (3)
Solution: (3)
Circumference of circle $=2 \pi r$
$\Rightarrow 572=2 \times \frac{22}{7} \times r$
$\Rightarrow r=\frac{572 \times 7}{2 \times 22}=91$
$\therefore$ Length of floor $=91+6$ $=97$ metre $=l$
$\therefore 2(l+b)=356$
$\Rightarrow 2(97+b)=356$
$\Rightarrow 97+b=178$
$\Rightarrow b=178-97=81$ metre
$\therefore$ Area of floor $=97 \times 81$ $=7857$ sq. metre
$\therefore$ Required cost $=12 \times 7857$ $= \text{₹} 94284$
BETA
