How To Solve Cube And Cuboid Quickly

how to solve cube and cuboid question 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 much is a three inch cube of silver worth ?

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

Answer: Option B


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

Answer: Option A


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

Answer: Option C


how to solve question and answer quickly


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

Answer: Option A


cube and cuboid how to solve question


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

= 4 + 4 + 2

= 10