Question

The cost of papering four walls of a room at $14Rs.$ per square metre is $3,150Rs.$ The height of the room is $5$ metres. Find the length and the breadth of the room, if they are in the ratio $4:1.$

• A. $17m$ and $1.5m$
• B. $18m$ and $4.5m$
• C. $21m$ and $3.5m$
• D. $25m$ and $7.5m$

Answer 1

Answer: (B)

$18m$ and $4.5m$

Given, cost of papering the wall is Rs 3150 at Rs 14 per sq. m. Height of the room is 5m and length and breadth are in ratio 4:1.
$Areaofwalltobepapered=\frac{costofpaperingthewall}{rateofpaperingpermeter}=\frac{3150}{14}=225m^2$
The height of wall=5 cm. Let the length of the wall be 4$x$ and breadth be $x$.

Surface area of four walls$=2h(l+b)$
$or,225=2\times 5(4x+x)or,225=10\left(5x\right)or,225=50xor,x=4.5$
Length of wall$=4x=5\times 4.5=18m$.

Breadth of wall$=x=4.5m$