Question

A hall is 45 m long and 30 m broad. Allowing 90 m2 for doors and windows,
the cost of papering the walls with paper 75 cm wide at the rate of 50 paise
per m is Rs. 740. Find the height of the hall.​

Answer 1

Answer:

Length of hall = 36 m ; breadth of hall = 24 m

Let 'h' be height of the hall

Now in preparing the wall, we need to paper the four walls excluding floor and root of the hall.

so area of wall which is to be papered

=lh+bh+lh+bh=2h(l+b)=2h(36+24)=120hm

2

Now area leaves for doors and windows =80m

2

so the area which is actually papered =(120h−80)m

2

Again cost of papering the walls at Rs. 8.40 per m

2

is equal to Rs 9408.

(120h−80)×8.4=9408

120h−80=1120⇒120h=1200⇒h=10m.