Question

Self Assessment Sh
The four walls of a room can be fully covered by 70
square wall papers of 2 mx 2 m size. The length of
the room is 18 m and its breadth is twice that of its
height. If the cost of carpeting is 20 per square
metre, what will be the total expenditure in carpeting
the room?
(a) 1800
(b) * 5040
c) 3600
(d) 1400
​

Answer 1

Step-by-step explanation:

to find the cost of painting we need lateral surface area of the room ( LSA )

  LSA of room = 2h(l+b)    ; given that 4 * l = 1 * b i.e 4l = b and h = 5

therefore LSA = 2 * 5 ( l + 4l ) -------(1)

we can also get LSA by dividing total cost and cost per  sq.m

LSA = 157.50/0.70 = 225 -------(2)

eqn (1) = eqn (2)

10 ( l + 4l ) = 225

5l = 22.5

l = 4.5 m

b = 4l = 4 * 4.5

b = 18 m