(1) l : b : h = 8 : 7 : 5 Sum of the terms of ratio= 8 + 7 + 5 = 20 ∴ Length =
8
20
×24 = 9.6 metre Breadth =
7
20
×24 = 8.4 metre Height =
5
20
×24 = 6.0 metre ∴Area of the four walls of theroom = 2 × h (l + b) = 2 × 6 (9.6 + 8.4) = 12 × 18 = 216 sq. metre ∴Expenditure on painting = Rs. (216 × 12) = Rs. 2592