Question

26. किसी कमरे की लंबाई, चौड़ाई और ऊंचाई का अनुपात 3:3:4
में है। यदि लंबाई दोगुनी, चौड़ाई दो-तिहाई और ऊँचाई आधी की जाती
है तो कमरे की चार दीवारों को पेंट करने की लागत कितने प्रतिशत
तक कम हो जायेगी?​

Answer 1

Answer :

16 square units

Step by step explanation :

Here,

Original room's

Length ( l ) = 3

Breadth ( b ) = 3

Height ( h ) = 4

According to given condition,

Newly formed room's

Length ( l ) = 3 × 2 = 6

Breadth ( b ) = 3 × 2/3 = 2

Height ( h ) = 4 × 1/2 = 2

By using surface area of cuboid

= 2 ( l + b ) h

Therefore, surface area of original room

= 2 ( 3 + 3 ) 4

= 8 ( 6 )

= 48 square units

Therefore, surface area of newly formed room

= 2 ( 6 + 2 ) 2

= 4 ( 8 )

= 32 square units

as they have asked us about reduced percentage of required paint,

Therefore,

Reduced percentage =

( Surface area of original room - surface area of newly formed room ) 100 ÷ Surface area of original room

= ( 48 - 32 ) 100 ÷ 48

= ( 16 ) 100 ÷ 48

= 1600 ÷ 48

= 25 %

Therefore, requirement of paint for painting newly formed room will be reduced by 25 %

Hope u understood the concept