Non-verbal reasoning for SSC CGL

Non-verbal questions are the ones many candidates skip. The options look nearly identical, there is no formula, and the clock is running. That is a mistake, because these questions follow a small set of predictable transformations: reflection, rotation, folding and adding or removing parts. The four options usually differ in only one or two details.

So the skill is not "seeing" the answer. It is knowing exactly what each transformation does, then checking one element at a time until three options are gone.

How they appear in SSC CGL

Non-verbal items appear in the General Intelligence and Reasoning section of Tier 1 and in the Reasoning module of Tier 2. The mix varies between shifts. The common formats are:

Counting triangles and squares and dice questions are also non-verbal; they have their own guides on counting figures and dice and cubes.

Mirror images

A mirror placed to the side of an object (a vertical mirror line) swaps left and right. Top and bottom stay where they are.

• Capital letters that look the same in a vertical mirror: A, H, I, M, O, T, U, V, W, X, Y.
• In a word, two things happen: the order of letters reverses, and each letter is flipped. So a mirror image of "TOM" reads MOT from left to right, with the M, O and T each flipped (they look unchanged because they are symmetric).
• Letters like B, C, D, E, K look different in a vertical mirror, and letters such as N, S, Z become their reversed forms. Options often hide the error in exactly one such letter.

The clock mirror rule

Mirror time = 11:60 − actual time. This works for any time from 1:00 to 11:59. For times between 12:00 and 12:59, use 23:60 − actual time.

Why it works: a vertical mirror reflects each hand across the 12–6 line, so a hand at "x minutes past 12" appears at "x minutes before 12". The whole time t becomes 12:00 − t.

Water images

A water surface below the object is a horizontal mirror line. It swaps top and bottom. Left and right stay the same.

• Capital letters that look the same in water: B, C, D, E, H, I, K, O, X.
• In a water image of a word, the order of letters does not change. Each letter is simply turned upside down.

Paper folding and punching

When a folded sheet is punched and opened, every hole is reflected across each fold line. Each fold doubles the number of layers, so each fold doubles the holes from one punch.

Picture the square sheet as a 4 × 4 grid. Columns are A, B, C, D from left to right; rows are 1, 2, 3, 4 from top to bottom.

Worked example 1. The sheet is folded left half over right half (the fold runs between columns B and C). Then it is folded top half down over bottom half (the fold runs between rows 2 and 3). The folded packet now covers cells C3, D3, C4 and D4. One hole is punched through all layers in cell C4. Where are the holes after opening?

1. Undo the last fold first. Reflect across the line between rows 2 and 3: row 4 maps to row 1. Holes: C4 and C1.
2. Undo the first fold. Reflect across the line between columns B and C: column C maps to column B. Holes: C4, C1, B4, B1.

Answer: 4 holes, at B1, C1, B4 and C4. They sit symmetrically about both fold lines.

Worked example 2. Same two folds, but the punch is in cell C3, next to both folds. Unfolding gives C3 and C2, then B3 and B2. The four holes form a small square block in the centre of the sheet.

Method:

1. Unfold in reverse order, last fold first.
2. At each step, reflect every hole across that fold line.
3. Count the holes (layers × punches) and check their positions against the options.

Paper cutting

Cuts follow the same reflection rule. A cut made on a folded edge opens into a shape that is symmetric about that fold.

Worked example. A square sheet is folded top half over bottom half. A small triangular notch is cut out of the middle of the folded (top) edge, with its point downwards. When opened, the notch is reflected upwards across the fold line. The result is a diamond-shaped hole in the centre of the sheet, not a triangle and not a notch on the edge.

Embedded figures

You are given a simple figure and asked which complex figure contains it.

• The simple figure must appear at the same size and orientation, unless the question says rotation is allowed.
• Pick its most distinctive feature (an unusual angle, a curve, a short extra line) and search for that first. Don't trace the whole figure in every option.

Figure series

Each figure changes from the one before by a fixed rule. Track elements separately:

Worked example. In a square frame, an arrow points up in figure 1, up-right in figure 2, right in figure 3 and down-right in figure 4. A small dot sits in the top-left corner in figure 1, top-right in figure 2, bottom-right in figure 3 and bottom-left in figure 4. What is figure 5?

• The arrow turns 45° clockwise each step, so figure 5 points down.
• The dot moves one corner clockwise each step, so figure 5 has it back in the top-left corner.

Eliminate every option with the arrow not pointing down, then check the dot among what remains.

Figure and pattern completion

• For a symmetric figure with one quarter missing, the missing part is usually a reflection of an adjacent quarter.
• For a 3 × 3 pattern of small figures, check each row and column for a repeating element or a count that rises by one.

Common mistakes

Practice

1. A clock shows 4:10. What does its mirror image show?
2. A clock shows 12:50. What does its mirror image show?
3. Which of these letters look the same in a vertical mirror: B, M, S, T, Z?
4. Which of these look the same in a water image: C, H, M, K, W?
5. A sheet is folded in half once and two holes are punched. How many holes appear when it is opened?
6. On the 4 × 4 grid above, the sheet is folded left half over right, then top half over bottom, and one hole is punched in D4. Where are the holes after opening?
7. A sheet is folded three times, making 8 layers, and one hole is punched. How many holes appear?
8. An arrow points left, then up, then right in three figures. Which way does it point in figure 4?

Answers

1. 7:50. 11:60 − 4:10 = 7:50.
2. 11:10. The time is between 12:00 and 12:59, so 23:60 − 12:50 = 11:10.
3. M and T. B, S and Z all change in a side mirror.
4. C, H and K. M and W turn into each other's shape upside down, so neither stays the same.
5. 4. One fold makes two layers; two punches through two layers make four holes.
6. A1, D1, A4 and D4. Undo the top fold: D4 and D1. Undo the side fold: A4 and A1. The holes sit in the four corners.
7. 8. One hole through 8 layers.
8. Down. It turns 90° clockwise each step: left, up, right, down.

What to do next

1. Write the two letter lists (mirror-safe and water-safe) and the clock rule on your revision sheet.
2. Practise folding with a real sheet of paper once. Fold, punch with a pen tip, open. Ten minutes of this fixes the reflection rule for good.
3. Do 15 mixed non-verbal questions a day for a week, and note which format costs the most time.
4. Move on to figural analogy, which uses the same one-element-at-a-time habit.