SSC CHSL Math Speed: Solve 25 Questions in 35 Minutes

SSC CHSL (Combined Higher Secondary Level) is conducted by the Staff Selection Commission for recruitment to Lower Divisional Clerk, Junior Secretariat Assistant, Postal Assistant, and Data Entry Operator posts. The quantitative aptitude section in Tier 1 contains 25 questions for 50 marks — and the entire Tier 1 paper must be completed in 60 minutes across four sections.

That means roughly 15 minutes per section — but experienced candidates allocate 35 minutes to math and reasoning combined, giving approximately 15–18 minutes to QA alone. At 25 questions in 15–18 minutes, the target is under 45 seconds per question. Speed is everything.

The difficulty level of SSC CHSL math is moderate — noticeably easier than SSC CGL Tier 1, but testing the same core topics. A candidate who has mastered SSC CGL math will find CHSL straightforward. For candidates preparing specifically for CHSL, this guide gives the exact topic-wise focus, shortcuts, and strategy to maximize scores efficiently.

For SSC CGL-level math strategy, refer to our SSC CGL Math Speed guide. For foundational arithmetic shortcuts, refer to our individual topic guides on SpeedMath.in.

Part 1: SSC CHSL Exam Pattern — Quantitative Aptitude

Tier 1 Pattern

Negative marking: 0.50 marks per wrong answer (2 marks per question, −0.50 wrong).

Key insight: Each correct answer = 2 marks. Each wrong answer = −0.50 marks. Net cost of attempting vs. leaving: attempt only when 75%+ confident.

Tier 2 Pattern (Skill Test)

Tier 2 is a skill/typing test — no math. Math matters only in Tier 1.

Part 2: Topic-Wise Weightage — SSC CHSL QA

Distribution of 25 Questions

Top 5 topics by question count: Geometry + Mensuration, Number System, Percentage, Profit-Loss, DI — master these five first.

Part 3: Number System — Fast 2–3 Marks

Number system questions in CHSL test divisibility, remainders, factors, and unit digit calculations.

Divisibility Rules — Must Know

Worked Example 1:
Which of these is divisible by 11? (a) 9867 (b) 8536

9867: (9+6) − (8+7) = 15−15 = 0 → divisible by 11 ✓
Answer: 9867

Unit Digit Calculation

Worked Example 2:
Find unit digit of 7⁹⁵

Unit digits of powers of 7 cycle: 7,9,3,1,7,9,3,1 (cycle of 4)
95 ÷ 4 = remainder 3
3rd in cycle = 3

Remainder Problems

Worked Example 3:
What is the remainder when 2⁵⁰ is divided by 3?

Powers of 2 mod 3: 2,1,2,1... (cycle of 2)
50 is even → remainder = 1

Part 4: Percentage and Profit-Loss — 4–6 Marks

These two topics together contribute 4–6 questions — the highest combined weightage block in CHSL.

Percentage Shortcuts

1% method: Find 1% (move decimal 2 places left), multiply for any percentage.

Worked Example 4:
17.5% of 360

10% = 36, 5% = 18, 2.5% = 9
17.5% = 36+18+9 = 63

Fraction equivalents — memorize:

Profit-Loss Shortcuts

Multiplying factor method:
20% profit → SP = CP × 1.20
15% loss → SP = CP × 0.85

Worked Example 5:
A shopkeeper buys an item for Rs. 800 and marks it 40% above CP. He then gives 25% discount. Find SP and profit%.

MP = 800 × 1.40 = 1120
SP = 1120 × 0.75 = Rs. 840
Profit = 840−800 = 40 → Profit% = 40/800 × 100 = 5%

Shortcut formula — successive percentage:
Net % = x + y + xy/100

Where x = markup%, y = −discount% (negative for discount)
= 40 + (−25) + (40×(−25))/100 = 40−25−10 = +5% ✓

Part 5: Simple and Compound Interest

1–2 questions — target full marks with these shortcuts.

SI formula: SI = PRT/100

CI for 2 years shortcut:
CI = SI + (SI of SI for 1 year)
= PRT/100 + (P × r²/10000)

Worked Example 6:
Rs. 5,000 at 8% per annum. Find SI and CI for 2 years.

SI = 5000 × 8 × 2/100 = Rs. 800

CI = 5000 × (1.08)² − 5000
= 5000 × 1.1664 − 5000
= 5832 − 5000 = Rs. 832

Difference = 832−800 = Rs. 32 (= SI × r/100 = 400 × 8/100 = 32 ✓)

Part 6: Time, Speed and Distance

1–2 questions — use direct formula application.

Core formulas:
Speed = Distance/Time
Relative speed (same direction) = S₁ − S₂
Relative speed (opposite direction) = S₁ + S₂

Worked Example 7:
A train 200m long crosses a pole in 10 seconds. Find speed in km/h.

Speed = 200/10 = 20 m/s
= 20 × 18/5 = 72 km/h

Worked Example 8:
Two trains 150m and 250m long run at 60 and 40 km/h toward each other. Time to cross?

Relative speed = 100 km/h = 100 × 5/18 = 250/9 m/s
Total length = 400m
Time = 400 ÷ 250/9 = 400 × 9/250 = 14.4 seconds

Part 7: Time and Work

1–2 questions — LCM method is fastest.

Worked Example 9:
A does a job in 12 days, B in 15 days. Working together, time to finish?

LCM(12,15) = 60 units
A = 5 units/day, B = 4 units/day
Together = 9 units/day
Time = 60/9 = 6.67 days

Worked Example 10:
A and B together finish in 8 days. B alone in 12 days. A alone?

A's rate = 1/8 − 1/12 = 3/24 − 2/24 = 1/24
A alone = 24 days

Part 8: Geometry and Mensuration — 3–4 Marks

Highest single-topic weightage in CHSL. Focus on triangles, circles, and quadrilaterals for geometry — and rectangle, circle, cylinder for mensuration.

Must-Know Geometry Properties

Triangle:
Sum of angles = 180°
Exterior angle = sum of two non-adjacent interior angles
Pythagoras: a² + b² = c²

Common Pythagorean triplets: 3-4-5, 5-12-13, 8-15-17, 7-24-25

Circle:
Angle in semicircle = 90°
Angles in same segment are equal
Tangent ⊥ radius at point of contact

Worked Example 11:
In a triangle, two angles are 65° and 75°. Find the third angle.

Third angle = 180 − 65 − 75 = 40°

Worked Example 12:
Find area of triangle with sides 5, 12, 13.

5-12-13 is a Pythagorean triplet → right triangle
Area = ½ × 5 × 12 = 30 sq units

For complete mensuration formulas — refer to our Mensuration guide.

Part 9: Trigonometry and Algebra

1–2 questions each — focus on standard values and identities only.

Trigonometry — 3 Must-Know Identities

sin²θ + cos²θ = 1
1 + tan²θ = sec²θ
1 + cot²θ = cosec²θ

Worked Example 13:
If sinθ = 3/5, find cosθ and tanθ.

cosθ = √(1 − 9/25) = √(16/25) = 4/5
tanθ = sinθ/cosθ = (3/5)/(4/5) = 3/4

Algebra — Key Identities

(a+b)² = a² + 2ab + b²
(a−b)² = a² − 2ab + b²
a² − b² = (a+b)(a−b)
a³ + b³ = (a+b)(a² − ab + b²)

Worked Example 14:
If x + 1/x = 5, find x² + 1/x²

(x + 1/x)² = x² + 2 + 1/x²
25 = x² + 2 + 1/x²
x² + 1/x² = 23

Part 10: Data Interpretation — 2–3 Marks

CHSL DI is simpler than SBI PO — usually a single table or bar graph with 2–3 questions.

Worked Example 15 — Table DI:

Q1: Growth from 2021 to 2022?
= (480−400)/400 × 100 = 20%

Q2: Average sales over 3 years?
= (400+480+520)/3 = 1400/3 = 466.67 units

Part 11: Attempt Strategy — Tier 1

Time Allocation (Full Paper)

QA Attempt Order

Target: 20–22 attempts with 85%+ accuracy = 34–40 marks out of 50.

Safe Score for CHSL Selection

General category: 35–40 marks in QA is a comfortable score.
Cut-off varies by year — but 160+ out of 200 overall keeps you safe for Tier 2.

45-Day SSC CHSL Math Practice Plan