Question

find the cost of painting of the outer surface of a closed box which is 60cm long 25cm broad and 20cm high at rate of 35 paise per 20cm2​

Answer 1

Answer:

I hope you understand my answer

Answer 2

Answer :-

• Total Cost of painting = 112 Rs

Given :-

• Length of Box = 60 cm
• Breadth of Box = 25 cm
• Height of Box = 20 cm
• Rate of painting = 35 p = 0.35 Rs / cm²

To Find :-

• Total Cost of painting = ?

Explanation :-

As above given, we have find the total cost of painting the outer surface of the box which include the :- All 4 faces, Top and Bottom. Hence, we will find the TSA of Box.

Finding TSA of Box,

$\green { \boxed { \bf \bigstar \: TSA \: of \: Box = 2 \: (LB + BH + HL) \: \bigstar }}$

$\rm : \: \leadsto 2 \: (LB + BH + HL) = TSA \: of \: Box$

$\rm : \: \leadsto 2 \: [ \: 60(25) + 25(20) + 20(60) \: ] \: cm^2$

$\rm : \: \leadsto 2 \: [ \: 1500 + 500 + 1200 \: ] \: cm^2$

$\rm : \: \leadsto 2 \: (3200) \: cm^2$

$\blue { \bf : \: \leadsto 6400 \: cm^2 \: \: \star}$

Now, Finding Cost of painting the Box,

$\rm : \: \leadsto Cost \: of \: Painting \: 20 \: cm^2 = \bold{0.35 \: R_S}$

$\rm : \: \leadsto Cost \: of \: Painting \: 1 \: cm^2 = \bold{\dfrac{35}{2000} \: R_S}$

$\rm : \: \leadsto Cost \: of \: Painting \: 6400 \: cm^2$

               $\rm = 6400 \times \dfrac{35}{2000} \: R_S$

               $\rm = \dfrac{224000}{2000} \: R_S$

              $\red { \underline { \boxed { \bf \star \: = 112 \: R_S \: \star }}}$

Hence, the cost of painting the outer surface of the box is 112 Rs.