# How To Solve Cube And Cuboid Quickly ## How To Solve Cube And Cuboid Questions Quickly

Cuboid and Cube have the basic formulas to understand and learn for the exact solutions of the questions . One has to be very precise and have clear concept of  cuboid and cube to learn and analyse the basic details of the problems . ## Surface Area of Cuboid:

• Before delving into the concept of surface areas and volumes of cube and cuboid, it is essential that we learn to make them.
• A cuboid is a three-dimensional representation of a rectangle while a cube is the three-dimensional representation of a square.
• Cuboid is an assemblage of rectangular pieces, similarly, a cube is an assemblage of square shaped pieces as length, breadth, and height.

## Surface Area of Cube:

A cube is a 3d representation of a square and has all equal sides. The length, breadth, and height in a cube are the same and are termed as sides (s). If s is each edge of the cube then, the surface area of a cube:

• 2 [(s × s) + (s × s) + (s × s)] = 2 ( 3s2) = 6s2

### Question 1.

A 2 inch cube(2*2*2) of silver weighs 1.5 kilos and is worth Rs1000.how much is a three inch cube of silver worth ?

(A) 18750
(B) 33750
(C) 22500
(D) 28000

#### Explanation:

8 inch cube = Rs 1000
1 inch cube = Rs 1000/8 = rs 125
27 inch cube = Rs 125*27 = Rs 3375

### Question 2.

All faces of a cube with an eight – meter edge are painted red.  If the cube is cut into smaller cubes with a two – meter edge, how many of the two meter cubes have paint on exactly one face?

(A) 24
(B) 36
(C) 60
(D) 48

#### Explanation:

If there are n cubes lie on an edge, then total number of cubes with one side painting is given by 6×(n−2)2. Here side of the bigger cube is 8, and small cube is 2. So there are 4 cubes lie on an edge. Hence answer = 24.

## How To Solve Cube and Cuboid Questions Quickly:

The following questions are based on the information given below:

1. There is a cuboid whose dimensions are 4 x 3 x 3 cm.
2. The opposite faces of dimensions 4 x 3 are coloured yellow.
3. The opposite faces of other dimensions 4 x 3 are coloured red.
4. The opposite faces of dimensions 3 x 3 are coloured green.
5. Now the cuboid is cut into small cubes of side 1 cm.

### Question 3.

How many small cubes will have only two faces colored?

(A) 12
(B) 24
(C) 13
(D) 16

#### Explanation: Number of small cubes having only two faces coloured = 6 from the front + 6 from the back + 2 from the left + 2 from the right

= 16

### Question 4 .

How many small cubes will have only one face coloured ?

(A) 10
(B) 12
(C) 14
(D) 18

#### Explanation: Number of small cubes having only one face coloured = 2 x 2 + 2 x 2 + 2 x 1

= 4 + 4 + 2

= 10 