14. Find the length of a floor whose breadth is 4 m and which can be covered by 2400 tiles of ve
25 cm by 20 cm
15. A room is 7-5 m long, 2.5 m wide and 1.5 m high. It has one window measuring (50 cm by 25cm
and a door measuring (1 m by 0-5 m). Find the cost of painting its four walls at 100 per mi?
16. The width of a cloth is 20 cm. Calculate the length of the cloth to make 10 pieces of size 20 cm
by 5 cm
17. The area of the 4 walls of a room is 400 m². The length and breadth of room are 15.5 m and 46
m respectively. Find the height of the room.
please give me the answer fast I need it urgent
Answers
Answer:
14. Breadth of floor = 4m = 400cm
Area of tiles = 25×20 = 500cm²
No of tiles = 2400
Total area = 2400×500 = 1200,000cm²
Area : lb = 1200,000
l×400 = 1200000
l = 1200000/400 = 3000cm = 30m
15. l = 7.5m b=2.5m h=1.5m
Area = 2(lb+bh+lh)
= 2(18.75+3.75+11.25)
= 2×33.75 = 67.5m²
Area of window = 0.5×0.25 = 0.125m²
Area of door = 1×0.5 = 0.5m²
Remaining area = 67.5 - 0.5 - 0.125= 66.875
Cost of painting = 100/m²
Cost = 66.875×10 = 6687.5
16. l = ? b = 20cm
Area of piece = 20×5 = 100cm²
Area required = 10×100 = 1000cm²
lb = 1000
l = 1000/20 = 50cm
17. Lateral area = 2h(l+b) = 400m²
l = 15.5m b = 46m h=?
2h(l+b) = Area
2×h×(15.5+46) = 400
123h = 400
h = 400/123 = 3.252m (approx.)