Q&A: practice questions with answers

Concept: Compare each option part by part (house no., locality, area, city, PIN) with the sample.

1. (A) has 'House 25' – the word 'No.' is missing.
2. (C) has 'South Delhi' in place of Saket and PIN 110007.
3. (D) has house number 35 instead of 25.
4. (B) agrees in every part.

Trick: Check the numbers first (house no. and PIN) – most wrong options differ there; then scan the words.

Answer: (B) House No. 25, Green Park, Saket, New Delhi - 110017

Concept: Days after = later date − earlier date (same month).

1. Nagpur seminar: 11 Feb.
2. Mysuru seminar: 17 Feb.
3. Gap = 17 − 11 = 6 days.

Trick: Ignore the other six cities – only the two dates asked matter.

Answer: (A) 6 days

Concept: Find the hidden rule from the solved examples and apply it to the new pair.

1. $5\times 6=30$, shown as 31 → +1.
2. $6\times 7=42$, shown as 43 → +1. Rule: $a\times b+1$.
3. $7\times 8=56$ → $56+1=57$.

Trick: Compare the shown result with the real product: the difference (+1 here) is the whole rule.

Answer: (C) 57

Concept: The result is the product plus the first number, i.e. $a\times (b+1)$.

1. $3\times 4=12$, shown 15 → +3; $4\times 5=20$, shown 24 → +4.
2. $5\times 6=30$, shown 35 → +5. The extra is always the first number.
3. $6\times 7+6=42+6=48$.

Trick: $a\times b+a=a\times (b+1)$: $6\times 8=48$ in one step.

Answer: (A) 48

Concept: For any two numbers, their product equals $\text{HCF}\times \text{LCM}$.

1. Here $1800=20\times \text{LCM}$.
2. So $\text{LCM}=\frac{1800}{20}=90$.

Yaad rakhein: This product rule is valid only for TWO numbers, not for three or more.

Answer: (B) 90

Concept: Add the given equations and cancel common terms to get a new relation.

1. A + B = 2C and C + D = 2A.
2. Adding: A + B + C + D = 2A + 2C.
3. Subtract A + C from both sides: B + D = A + C.

Trick: Test with numbers: A = 2, C = 3 → B = 4, D = 1. Then A + C = 5 = B + D; other options fail.

Answer: (A) A + C = B + D

Concept: Group items by category; the one outside the common category is the answer.

1. Chrome, Firefox and Edge are software used to open websites (web browsers).
2. Intel is a hardware company that makes processors (CPUs).
3. So Intel does not belong to the group.

Trick: Ask 'Can I open a website with it?' – only Intel gives a 'No'.

Answer: (D) Intel

Concept: Speed = Distance ÷ Time, with time converted into hours.

1. 1 h 15 min = $1+\frac{15}{60}=\frac{5}{4}$ h.
2. Speed = $100÷\frac{5}{4}=100\times \frac{4}{5}$.
3. = 80 km/h.

Trick: 75 min for 100 km → in 60 min: $100\times \frac{60}{75}=80$ km/h.

Answer: (C) 80 km/h

Concept: Find the operation linking the first pair and repeat it on the second pair.

1. $574÷7=82$ ✓ ($7\times 82=574$).
2. Apply the same: $21÷7=3$.

Trick: If the second number is much smaller, try dividing; $574=7\times 82$ is quick to verify ($7\times 80=560$, $+14$).

Answer: (C) 3

Concept: Add digits repeatedly until a single digit remains.

1. (A) digit total of 852963 is 33; then 3 + 3 = 6 ✓
2. (B) total 27 gives root 9; (C) total 21 gives root 3.
3. (D) total 52 gives root 7.

Trick: Digital root = remainder on dividing by 9 – so cast out 9s: in 852963 drop 9 and 6+3; left 8+5+2 = 15 → 6.

Answer: (A) 852963

Concept: Same centre means the first three digits must be identical.

1. (A) 452239 and 452890 → 452 = 452 ✓
2. (B) 672 vs 673, (C) 781 vs 782, (D) 452 vs 453 – all differ in the third digit.

Trick: Look only at the third digit once the first two match – that is where every trap is placed.

Answer: (A) 452239 and 452890

Concept: 'All X are Y' always gives 'Some X are Y'; two particular links do not give a definite conclusion.

1. Teachers circle lies fully inside Educated.
2. Scientists touch Educated, but can be drawn away from Teachers → I is only possible, not certain.
3. All teachers are educated ⇒ some teachers are educated → II follows.

Trick: 'All A are B' → 'Some A are B' is always true (conversion of 'All' to 'Some').

Answer: (B) Only II follows

Concept: A conclusion follows only if it is true in every possible diagram.

1. Dogs ⊂ Animals; Wild is only some part of Animals; Wild and Domestic are separate.
2. Dogs may lie outside Wild, even entirely Domestic → I (some dogs not domestic) is not certain.
3. 'All dogs are animals' cannot be reversed to 'All animals are dogs' → II fails.

Trick: 'All A are B' never converts to 'All B are A' – reject such conclusions instantly.

Answer: (D) Neither I nor II follows

Concept: Convert letters to positions and find the constant gap.

1. H = 8, L = 12, P = 16, T = 20 → +4 each time.
2. Next = 20 + 4 = 24 = X.

Trick: Use EJOTY (5, 10, 15, 20, 25): T = 20, so 24 is just before Y → X.

Answer: (B) X

Concept: Every letter of the option (with its count) must be present in the given word.

1. DEVELOPMENT letters: D, E×3, V, L, O, P, M, N, T.
2. DEEP uses D, two E's and P – each is there ✓
3. A (for MADE, PLANT) and B (for BEND) do not occur in DEVELOPMENT.

Trick: Spot a letter missing from the main word (A, B) and strike out those options first.

Answer: (A) DEEP

Concept: Each letter of the word is replaced by its next letter.

1. N→O, E→F, H→I, R→S, U→V: every letter +1.
2. G→H, A→B, N→O, D→E, H→I, I→J.
3. GANDHI = HBOEIJ.

Trick: Check only the 3rd letter: N+1 = O – only option (B) has O there.

Answer: (B) HBOEIJ

Concept: Treat the first and second letters as two separate series.

1. First letters: C, E, G → +2 → I.
2. Second letters: H, J, L → +2 → N.
3. Next pair = IN.

Trick: In each pair the second letter is 5 ahead of the first (C→H); I + 5 = N.

Answer: (D) IN

Concept: Each term = previous term × 2 + 1.

1. Double and add one: $15=7\times 2+1$; $31=15\times 2+1$; $63=31\times 2+1$ ✓
2. So the next term = $63\times 2+1=127$.

Trick: Terms are $2^n-1$ ($8-1$, $16-1$, $32-1$, $64-1$) → next $128-1=127$.

Answer: (C) 127

Concept: First term is $n^2$, second is $n^3$ of the same n.

1. $225={15}^2$, $3375={15}^3$.
2. $256={16}^2$ → answer ${16}^3$.
3. ${16}^3=256\times 16=4096$.

Trick: Cube of n = square × n: $256\times 16=4096$. Option 3375 is just a repeat trap.

Answer: (D) 4096

Concept: Each term = previous × 2 + 1 (all terms are one less than a power of 2).

1. $63=64-1$, $127=128-1$, $255=256-1$ … $1023=1024-1$.
2. Next = $2048-1=2047$ (or $1023\times 2+1$).

Trick: Know powers of 2 up to $2^{12}$ (4096) – such series become one-glance questions.

Answer: (A) 2047