A tank is 25 m long, 12 m wide and 6 m deep. The cost of plastering its walls and bottom at 75 paise per sq. m, is:
Rs. 456
Rs. 458
Rs. 558
Rs. 568
Explanation:
Area to be plastered= $[2\left(l + b\right) \times h] $+ $\left(l \times b\right)$ = ${[2\left(25 + 12\right) \times 6] + \left(25 \times 12\right)}$ m2 = (444 + 300) m2 = 744 m2. |
$\therefore$ Cost of plastering = Rs.$ \left(744 \times\dfrac{75}{100} \right) $= Rs. 558. |