Solved UPSC CDS/OTA Question
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Q · Mensuration Medium · 45s
The dimensions of a room are 24 feet x 18 feet x 12 feet. What is the cost of white washing the four walls of the room at Rs. 6 per square feet if there is one door of dimensions 6 feet x 4 feet and three windows of dimensions 6 feet x 3 feet each?
TopicMensuration
Question Typemultiple choice
DifficultyMedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
The complete worked solution.
Every step explained — no skipped algebra.
Area of the four walls = 2h(l + b)
Since there are doors and windows, area of the walls = 2 x 12 (24 +18 ) - (6 x 4) - 3(6 x 3)
=930 sq.ft.
Total cost = 930 x 6 = Rs. 5580
Final Answer: Option B — Rs. 3600