Reasoning

ISBT Reasoning for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams

Previous12Next

Q1.
Direction  :  A cube is painted red and all its faces and is then divided into 343 equal cubes.

How many cubes will have at least one face painted ?
1) 127 2) 178
3) 218 4) 279
5)None of these
Answer : 218
Explanation : The number of cubes whose at least one face is painted = One face painted + two face painted + three face painted = One face visible + two face visible + three face visible = Total - (No face visible) = 343 - 125 = 218
View Answer

Q2.
Direction  :  A cube is painted red and all its faces and is then divided into 343 equal cubes.
How many cubes have no face painted ?
1) 27 2) 64
3) 125 4) 216
5)None of these
Answer : 125
Explanation : The number of cubes where no face is painted = The number of cubes who one face is visible
 =  (a - 2)3 = (7 - 2)3 = 125.
View Answer

Q3.
Direction  :  A cube is painted red and all its faces and is then divided into 343 equal cubes.

How many cubes will have one face painted ?
1) 112 2) 148
3) 150 4) 162
5)None of these
Answer : 150
Explanation : The number of cubes whose one face is painted = The number of cubes who one face is visible = 6 (a - 2)2 = 6 (7 - 2)2 = 150
View Answer

Q4.
Direction  :  A cube is painted red and all its faces and is then divided into 343 equal cubes.

How may cubes will have two faces painted ?
1) 45 2) 50
3) 56 4) 60
5)None of these
Answer : 60
Explanation :
Since, the cube is divided into 343 equal cubes i.e. (7)3 equal cubes, assume the edge length of the cube to be 7, (a = 7). This is done using the idea of unit cubes. (A cube of edge length a unit can be divided into a3 unit cubes)

The number of cubes whose two faces are painted = The number of cubes whose two faces are visible = 12 (a - 2) = 12 (7 - 2) = 60
View Answer

Q5.
Direction  :  A cube is painted red and all its faces and is then divided into 343 equal cubes.

How many cubes will have three faces painted ?
1) 0 2) 4
3) 8 4) 16
5)None of these
Answer : 8
Explanation :
Since the cube is divided into 343 equal cubes i.e. (7)3 equal cubes, assume the edge length of the cube to be 7, (a = 7). This is done using the idea of unit cubes. (A cube of edge length a unit can be divided into a3 unit cubes)

The number of cubes whose three face are painted is equal to the number of cubes whose three faces are visible. (Since only those faces which are visible can be painted). 
Hence, the number is 8.
View Answer

Q6.
Directions : Study the following information and answer the questions given below.
        a. A rectangular wooden block is having length 6 cms, breadth 4 cms and-height 1 cm.
b. Both sides having dimensions 4 cm x 1 cm are painted in-black colour.
c. Both sides having dimensions 6 cm x 1 cm are painted in red colour.
d. Both sides with dimensions 6 cm x 4 ,cm are painted in green colour.
e.  The block is cut into six equal parts of 1 cm, each (from 6 cm side) and into 4 equal parts of 1                    cm each (from 4 cm side).
If cubes having only  "black as weft as green " colour are removed, then how many cubes will remain?
1) 4 2) 8
3) 16 4) 20
5)None of these
Answer : 16
Explanation :
Number of cubes with black and green colours are 8. Remaining cubes = 24 - 8 = 16
View Answer

Q7.
Directions : Study the following information and answer the questions given below.
        a. A rectangular wooden block is having length 6 cms, breadth 4 cms and-height 1 cm.
b. Both sides having dimensions 4 cm x 1 cm are painted in-black colour.
c. Both sides having dimensions 6 cm x 1 cm are painted in red colour.
d. Both sides with dimensions 6 cm x 4 ,cm are painted in green colour.
e.  The block is cut into six equal parts of 1 cm, each (from 6 cm side) and into 4 equal                                   parts of 1 cm each (from 4 cm side).

How many cubes will be formed ?
1) 4 2) 8
3) 12 4) 24
5)None of these
Answer : 24
Explanation : Total number of cubes = 6 x 4 = 24
View Answer

Q8.
Directions : Study the following information and answer the questions given below.
        a. A rectangular wooden block is having length 6 cms, breadth 4 cms and-height 1 cm.
b. Both sides having dimensions 4 cm x 1 cm are painted in-black colour.
c. Both sides having dimensions 6 cm x 1 cm are painted in red colour.
d. Both sides with dimensions 6 cm x 4 ,cm are painted in green colour.
e. The block is cut into six equal parts of 1 cm, each (from 6 cm side) and into 4 equal parts of                 1cm each (from 4 cm side).

How many cubes will have all three colours black, green and red each at least on one side?
1) 2 2) 4
3) 8 4) 12
5)None of these
Answer : 4
Explanation :
Questions on rectangular block are to be proceeded in the same way as the questions on cube. But one important point-length, breadth and height are different in rectangular block.
Cubes with three colours will obviously be lying at the corner of the given rectangular block. Since there are lour corners so the number of such cubes will be 4.
View Answer

Q9.
A cube of size 3 cms whose opposite faces have been painted green, red and blue respectively and the cube is cut into smaller cubes of size 1 cm each.

Find out the number of smaller cubes with no face painted.
1) 1 2) 2
3) 4 4) D.I
5)None
Answer : 1
Explanation : The cube of this category will be one in number and located in the centre of the cube.
View Answer

Q10.
A cube of size 3 cms whose opposite faces have been painted green, red and blue respectively and the cube is cut into smaller cubes of size 1 cm each.

Find out the number of smaller   cubes   with   one   face painted.
1) 4 2) 6
3) 8 4) 12
5)None of these
Answer : 6
Explanation : The cubes of category (ii) with one face painted will be those lying in the centre of each face and this will be six in number.
View Answer

Previous12Next