About this quiz
Venn diagrams, counting figures, embedded figures, dot situation and rotation.
This Lok Sewa practice set has 52 multiple-choice questions (Subject: Mental Ability · For: Nayab Subba, Kharidar, Section Officer · Level: Medium). Take the quiz above first; after that, use the study list below to revise every question with its correct answer and a short explanation.
Study list: all 52 questions with answers and explanations
Which diagram best shows Kathmandu, Nepal and Asia?
- A) Three circles, one inside another ✔
- B) Three separate circles
- C) Two overlapping circles inside a third
- D) Three overlapping circles
Why: Kathmandu is part of Nepal, and Nepal is part of Asia, so the circles sit one inside another.
Which diagram best shows Dogs, Cats and Animals?
- A) Two separate circles inside a big circle ✔
- B) Three separate circles
- C) Three circles one inside another
- D) Two overlapping circles
Why: Dogs and cats are both animals but have no members in common, so two separate circles sit inside the big Animals circle.
Which diagram best shows Teachers and Women?
- A) Two overlapping circles ✔
- B) One inside the other
- C) Two separate circles
- D) Same circle
Why: Some women are teachers and some teachers are women, so the circles overlap.
Which diagram best shows Chairs and Rivers?
- A) Two separate circles ✔
- B) Overlapping circles
- C) One inside the other
- D) Concentric circles
Why: Chairs and rivers have nothing in common, so they are two separate circles.
Which diagram best shows Doctors, Women and Human beings?
- A) Two overlapping circles inside a big circle ✔
- B) Three separate circles
- C) Three concentric circles
- D) Two separate circles inside a big one
Why: All doctors and women are human beings, and some women are doctors, so two overlapping circles sit inside the big circle.
Which diagram best shows Fruits, Mangoes and Vegetables?
- A) Mango inside Fruits, Vegetables separate ✔
- B) All three overlapping
- C) All three concentric
- D) All separate
Why: All mangoes are fruits, so Mangoes sits inside Fruits; Vegetables are a separate group.
Which diagram best shows Nepalis, Farmers and Students?
- A) Farmers and Students overlapping inside Nepalis ✔
- B) All separate
- C) All concentric
- D) Nepalis inside Farmers
Why: Taking these as Nepali farmers and students, some are both, so the two overlap inside the Nepalis circle.
Which diagram best shows Sun, Moon and Stars?
- A) Sun inside Stars, Moon separate ✔
- B) All overlapping
- C) Moon inside Sun
- D) All concentric
Why: The Sun is a star, so it sits inside Stars; the Moon is not a star, so it is separate.
30 people like tea, 20 like coffee and 10 like both. How many like at least one?
- A) 40 ✔
- B) 50
- C) 60
- D) 30
Why: At least one = 30 + 20 − 10 = 40.
In a class of 50, 30 play football, 25 play cricket and 10 play both. How many play neither?
- A) 5 ✔
- B) 10
- C) 15
- D) 0
Why: At least one = 30 + 25 − 10 = 45, so neither = 50 − 45 = 5.
40 students passed Nepali, 35 passed English and 20 passed both. How many passed at least one?
- A) 55 ✔
- B) 75
- C) 60
- D) 20
Why: At least one = 40 + 35 − 20 = 55.
In a Venn diagram of 2 groups, the overlapping part shows:
- A) Members belonging to both groups ✔
- B) Members of neither
- C) Only group A
- D) Only group B
Why: The overlap shows members who belong to both groups.
How many squares are there in a 2 × 2 grid?
- A) 5 ✔
- B) 4
- C) 6
- D) 8
Why: 4 small squares + 1 big square = 5.
How many squares are there in a 3 × 3 grid?
- A) 14 ✔
- B) 9
- C) 10
- D) 13
Why: 9 (1×1) + 4 (2×2) + 1 (3×3) = 14.
How many squares are there in a 4 × 4 grid?
- A) 30 ✔
- B) 16
- C) 25
- D) 20
Why: 16 + 9 + 4 + 1 = 30. The rule is 1² + 2² + … + n².
How many rectangles (including squares) are in a 2 × 2 grid?
- A) 9 ✔
- B) 5
- C) 4
- D) 6
Why: A 2 × 2 grid has 3 horizontal and 3 vertical lines: 3C2 × 3C2 = 3 × 3 = 9.
How many rectangles (including squares) are in a 1 × 3 strip?
- A) 6 ✔
- B) 3
- C) 4
- D) 9
Why: A strip of 3 cells has 4 vertical lines: choose 2 of them = 4C2 = 6.
Lines from the top of a triangle divide its base into 3 parts. How many triangles are formed?
- A) 6 ✔
- B) 3
- C) 4
- D) 9
Why: There are 4 lines from the top; any 2 make a triangle: 4C2 = 6.
Lines from the top of a triangle divide its base into 4 parts. How many triangles are formed?
- A) 10 ✔
- B) 4
- C) 8
- D) 12
Why: There are 5 lines from the top: 5C2 = 10 triangles.
Lines from the top of a triangle divide its base into 2 parts. How many triangles?
- A) 3 ✔
- B) 2
- C) 4
- D) 6
Why: There are 3 lines from the top: 3C2 = 3 triangles.
A square with both diagonals drawn has how many triangles?
- A) 8 ✔
- B) 4
- C) 6
- D) 10
Why: 4 small triangles + 4 larger ones (each half of the square) = 8.
A rectangle divided into 3 equal parts by 2 vertical lines has how many rectangles?
- A) 6 ✔
- B) 3
- C) 4
- D) 5
Why: There are 4 vertical lines: 4C2 = 6 rectangles.
The best method to count figures accurately is to:
- A) Label points and count systematically ✔
- B) Guess quickly
- C) Count only big shapes
- D) Count only small shapes
Why: Label each point with a letter and count systematically, by size or by starting point, so nothing is missed or repeated.
In embedded figure questions, the hidden figure must appear in:
- A) The same size and orientation ✔
- B) Any size
- C) Rotated form always
- D) Mirror form always
Why: The hidden figure must appear with the same size and the same orientation, not turned or enlarged.
An embedded figure question asks you to find:
- A) A simple figure hidden in a complex one ✔
- B) The mirror image
- C) The next figure in a series
- D) The odd one out
Why: You find a simple figure hidden inside a more complex one.
In dot situation questions, the new dot must satisfy:
- A) Exactly the same conditions as the original dot ✔
- B) Any condition
- C) Only one condition
- D) No condition
Why: The new dot must be in a region with exactly the same conditions: inside and outside the same shapes as the original dot.
A dot is inside a circle and a triangle but outside a square. In the answer figure you need a region that is:
- A) Common to circle and triangle, not in the square ✔
- B) Inside all three
- C) Inside only the square
- D) Outside all shapes
Why: You need a region common to the circle and triangle that is not inside the square.
Clock hands move in which direction?
- A) Clockwise ✔
- B) Anticlockwise
- C) Upward only
- D) Randomly
Why: Clock hands move clockwise: from 12 to 3 to 6 to 9.
A figure turned 360° looks:
- A) The same as the original ✔
- B) Upside down
- C) Mirror reversed
- D) Turned 90°
Why: A full 360° turn brings the figure back to its original position.
A figure turned 180° appears:
- A) Upside down ✔
- B) Unchanged
- C) Turned 90° right
- D) Mirror reversed only
Why: A 180° turn makes the figure appear upside down (and left–right reversed).
An arrow pointing up is turned 90° clockwise. It now points:
- A) Right ✔
- B) Left
- C) Down
- D) Up
Why: Up turned 90° clockwise points right.
An arrow pointing right is turned 90° anticlockwise. It now points:
- A) Up ✔
- B) Down
- C) Left
- D) Right
Why: Right turned 90° anticlockwise points up.
An arrow pointing north is turned 135° clockwise. It points:
- A) South-east ✔
- B) South-west
- C) North-east
- D) East
Why: 90° clockwise from north is east; another 45° gives south-east.
A mirror image swaps:
- A) Left and right ✔
- B) Top and bottom
- C) Colours
- D) Size
Why: A side mirror swaps left and right, keeping top and bottom.
A water image swaps:
- A) Top and bottom ✔
- B) Left and right
- C) Colours
- D) Size
Why: A water image (reflection below) swaps top and bottom, keeping left and right.
In a mirror placed to the right, the letter "b" looks like:
- A) d ✔
- B) p
- C) q
- D) b
Why: Flipping left–right turns 'b' into 'd'.
In a water image, the letter "b" looks like:
- A) p ✔
- B) d
- C) q
- D) b
Why: Flipping top–bottom turns 'b' into 'p'.
When choosing pieces to form a square, the total area of pieces must:
- A) Equal the area of the square ✔
- B) Be larger
- C) Be smaller
- D) Not matter
Why: The pieces' total area must equal the square's area; otherwise there will be gaps or overlaps.
Pieces forming a triangle must fit:
- A) Without gaps or overlaps ✔
- B) With gaps
- C) With overlaps
- D) In any way
Why: They must fit exactly, without gaps or overlaps.
Total = A + B − (A and B) is used for:
- A) Two overlapping groups ✔
- B) Separate groups only
- C) Calendar problems
- D) Mirror images
Why: This formula counts members of two overlapping groups without counting the overlap twice.
If 25 people read paper A, 15 read paper B, and none read both, how many read at least one?
- A) 40 ✔
- B) 25
- C) 10
- D) 15
Why: With no overlap: 25 + 15 = 40.
Which diagram best shows Pen, Pencil and Stationery?
- A) Two separate circles inside a big circle ✔
- B) Three separate circles
- C) Three concentric circles
- D) Two overlapping circles inside one
Why: Pens and pencils are both stationery but different items: two separate circles inside a big circle.
Which diagram best shows Mother, Women and Doctors?
- A) Mothers inside Women; Doctors overlapping both ✔
- B) All separate
- C) All concentric
- D) Doctors inside Mothers
Why: All mothers are women (inside Women), and some women and some mothers are doctors (Doctors overlaps both).
Which diagram best shows Province, District and Ward (Nepal)?
- A) Three circles one inside another ✔
- B) All overlapping
- C) All separate
- D) Two separate inside one
Why: A ward is part of a local level in a district, and districts are in provinces, so three circles sit one inside another.
How many squares are there in a 5 × 5 grid?
- A) 55 ✔
- B) 25
- C) 50
- D) 30
Why: 25 + 16 + 9 + 4 + 1 = 55.
How many rectangles (including squares) are in a 3 × 3 grid?
- A) 36 ✔
- B) 14
- C) 9
- D) 27
Why: 4 horizontal and 4 vertical lines: 4C2 × 4C2 = 6 × 6 = 36.
How many triangles are formed if one diagonal is drawn in a square?
- A) 2 ✔
- B) 4
- C) 1
- D) 3
Why: One diagonal splits the square into 2 triangles.
In figure counting, a common mistake is:
- A) Counting the same shape twice ✔
- B) Labelling points
- C) Counting small shapes first
- D) Writing combinations
Why: A common mistake is counting the same shape twice, or missing larger shapes made of smaller parts.
Non-verbal reasoning questions mainly test:
- A) Ability to see patterns in figures ✔
- B) Spelling
- C) Grammar
- D) History
Why: They test the ability to see patterns, shapes and relationships in figures.
In a 2-circle Venn diagram, how many separate regions are inside the circles?
- A) 3 ✔
- B) 2
- C) 4
- D) 1
Why: Three: only A, only B, and both A and B.
In a 3-circle Venn diagram (all overlapping), how many regions are inside the circles?
- A) 7 ✔
- B) 6
- C) 8
- D) 3
Why: Seven: 3 'only one', 3 'exactly two', and 1 'all three'.
A clock shows 3:00 in a mirror. The real time is:
- A) 9:00 ✔
- B) 3:00
- C) 6:00
- D) 12:00
Why: Real time = 11:60 − 3:00 = 8:60 = 9:00.