Mensuration Ques 28

Question

The sum of the dimensions of a room (i.e. length, breadth and height) is 24 metres and its length, breadth and height are in the ratio of $8: 7: 5$ respectively. If the room is to be painted at the rate of Rs. 12 per $m^{2}$, what would be the total cost incurred on painting only the four walls of the room (in Rs.)?

(1) 2592

(2) 2648

(3) 2848

(4) 2120

(5) 1956

(IBPS RRBs Officer CWE (Pre.) 14.11.2016 (Shift-III))

Show Answer

Correct Answer: (1)

Solution: (1)

$l: b: h=8: 7: 5$

Sum of the terms of ratio $=8+7+5=20$

$\therefore$ Length $=\frac{8}{20} \times 24$ $=9.6$ metre

Breadth $=\frac{7}{20} \times 24$ $=8.4$ metre

Height $=\frac{5}{20} \times 24$ $=6.0$ metre

$\therefore$ Area of the four walls of the room $=2 \times h(l+b)$

$=2 \times 6(9.6+8.4)$

$=12 \times 18=216$ sq. metre

$\therefore$ Expenditure on painting $=$ Rs. $(216 \times 12)=$ Rs. 2592