Question

A wooden box with lid is made of $2.5cm$ thick. Inner length, breadth and height of box are $1m.65cm$ and $55cm$. Find the total expenditure of colouring its out surface area at the rate of $Rs.15$ per square meter.

Answer 1

According to the question-

Outer length of box $=100+5=105cm$

Outer breadth of box $=65+5=70cm$

Outer height of box $=55+5=60cm$

Therefore,

Surface area of box

$=2(lb+bh+hl)=2(105\times 70+70\times 60+60\times 105)=2(7350+4200+6300)=2\times 17850=35700cm=357m$

Given that the rate of colouring is $Rs.15$ per square meter.

Therefore,

Rate of colouring it's surface area $=15\times 357=Rs.5355$