Question

Can anyone explain it

Answer 1

Question :

Veena planned to make a jewellery box to gift her friend Reeta on her marriage. She made the jewellery box of wood in the shape of a cuboid. The jewellery box has the the dimensions as shown in the figure below. The rate of painting the exterior of the box is Rs. 2 per cm². After making the box she took help from his friends to decorate 5he box. The blue was painted by Deepak , black by Suresh, green by Harsh and the yellow was painted by Naresh.

Q1) What is the volume of the box?

Volume of cuboid = Length x Width x Height

= 30 cm² x 40cm² x 20 cm²

= 24000 cm²

Hence, (a) is the right option.

Q2) How much area did Suresh paint?

Side painted by Suresh is a rectangle with dimensions :-

So, by finding the area we'll get the answer

Area of rectangle = Length × Breadth

Area painted by Suresh = 20 × 40 = 800cm²

The bottom one is painted black

So the dimension of bottom part = 40 × 30 = 1200 cm².

Hence area painted by Suresh = 2000 cm²

Hence, (b) is the right option

Q3) How much area did Deepak paint ?

Let's take this as a cuboid, it means it a 3D figure of rectangle.

So AB = GH = 30 cm

Breadth = HE = 20 cm

Area shaded by Deepak will be

= 20 × 30 = 600 cm²

Deepak painted the other side too = 600 x 2

= 1200 cm²

Hence, (d) is the right option.

Q4) What amount did Harsh charge?

Let's take this as a Rectangle,

So, Side painted by Harsh = Length × Breadth

= 20 x 40 = 800cm²

Cost of painted side = 800 x Rs. 2

= Rs. 1600

Hence, (c) is the right option.

Q5) What amount did Veena pay for painting?

Cost for Naresh = Dimension of yellow painted area = 40 × 20 = 800 cm²

Cost for Deepak = 1200 x 2

= Rs. 2400

Cost for Suresh = 2000 x 2

= Rs. 4000

Cost for Harsh = 800 x 2

= Rs. 1600

Cost for Naresh = 800 x 2

= Rs. 1600

Total Cost = 2400 + 2400 + 1600 + 1600

= Rs. 8000

Hence, (d) is the right option.

Know more :-

Formulas :

• Volume of Cuboid

Volume = $l \: \times \: b \: \times h$

• Area of Rectangle

Area = $l \: \times b$