Q&A: practice questions with answers

Concept: Multiply the growth factors of each year.

1. $1.20\times 0.90=1.08$.
2. $1.08\times 1.15=1.242$.
3. Change $=24.2\%$ increase.

Trick: Base 100: $100\to 120\to 108\to 124.2$.

Answer: (B) 24.2% increase

Concept: Write all terms with base 2 and equate powers.

1. $2^{x+1}\times 2^{2(y-2)}=2^5$.
2. $x+1+2y-4=5\Rightarrow x+2y=8$.
3. $3y+2y=8\Rightarrow y=\frac{8}{5}=1.6$.

Trick: $4=2^2$ and $32=2^5$ — same base turns it into a linear equation.

Answer: (B) 1.6

Concept: Find A's present age, then use the ratio.

1. A now $=32-8=24$.
2. 4 parts $=24\Rightarrow 1$ part $=6$.
3. B $=5\times 6=30$ years.

Trick: B $=24\times \frac{5}{4}=30$.

Answer: (A) 30 years

Concept: Mean of an AP $=\frac{\text{first}+\text{last}}{2}$.

1. AP 3, 7, 11, …, 51 (common difference 4, 13 terms).
2. Mean $=\frac{3+51}{2}=27$.

Trick: In any AP the average equals the middle term (7th term $=3+6\times 4=27$).

Answer: (D) 27

Concept: Write decimals as reduced fractions: $\text{LCM}=\frac{\text{LCM of numerators}}{\text{HCF of denominators}}$.

1. $12.4=\frac{62}{5}$; $7=\frac{7}{1}$, $1=\frac{1}{1}$.
2. LCM $=\frac{\text{LCM}(7,62,1)}{\text{HCF}(1,5,1)}=\frac{434}{1}=434$.
3. Check: $434÷7=62$, $434÷12.4=35$ ✓.

Trick: Always reduce the fraction ($\frac{124}{10}\to \frac{62}{5}$) before taking LCM.

Answer: (C) 434

Concept: Write each letter's position: within a group the pattern is $n,n-1,n-3$; the first letters move back by 5.

1. First letters: M(13) → H(8) → C(3) → X(24) → S(19), each $-5$ (wrapping after A).
2. Inside each group: M L J $=13,12,10$; H G E $=8,7,5$; X W U $=24,23,21$.
3. So S(19), R(18), P(16) → SRP.

Trick: Check the first letters only: they step back by 5, so the answer starts with S; then $-1,-2$ gives SRP.

Answer: (B) SRP

Concept: Draw the family tree from the given links.

1. Malti is Lakhan's wife; Deepak is their son.
2. Bablu is Deepak's brother and Amrita is Bablu's sister, so Amrita is also a child of Lakhan.
3. Nehal is Lakhan's brother → Nehal is Amrita's father's brother (uncle, chacha).

Trick: Brother of father = paternal uncle (chacha).

Answer: (A) Father's brother

Concept: Look for third number $=$ first $\times$ (2 $\times$ second) $+1$.

1. $(18,6,217)$: $18\times 12+1=216+1=217$ ✓
2. $(21,6,253)$: $21\times 12+1=252+1=253$ ✓
3. $(23,4,185)$: $23\times 8+1=184+1=185$ ✓
4. Others: $22\times 10+1=221\ne 220$, $23\times 12+1=277\ne 276$, $24\times 12+1=289\ne 287$.

Trick: 217 and 253 are 1 more than multiples of 18 and 21 – that '+1' reveals the rule.

Answer: (D) (23, 4, 185)

Concept: Treat the three parts of each term separately.

1. First letter: Q, O, M, K → $-2$ each → I.
2. Number: 18, 23, 28, 33 → $+5$ → 38.
3. Last letter: N, P, R, T → $+2$ each → V.

Trick: Split each term into letter–number–letter and run three mini-series.

Answer: (B) I38V

Concept: Position from left $=$ total $-$ position from right $+1$. Facing North, 'left' means towards the left end.

1. Vinayak from left $=25-13+1=13$th.
2. Utkarsh is 4 places to the left of Vinayak → $13-4=9$th from the left.

Trick: Left + right position $=$ total $+1$.

Answer: (B) 9th

Concept: A word common to two sentences takes the code common to both.

1. 'energy' appears in both: 'rest restores energy' and 'positive energy attracts'.
2. Common code in 'rk fj mg' and 'tw es fj' is 'fj'.

Trick: Match the common word with the common code.

Answer: (D) fj

Concept: Scan for the pattern Even – Even – Odd and count the middle digit.

1. Position 4: 6 → 6 before (even), 3 after (odd) ✓
2. Position 13: 4 → 8 before, 3 after ✓
3. Position 21: 6 → 4 before, 1 after ✓
4. No other even digit has an even neighbour before and an odd one after.

Trick: First mark every odd digit, then look only at the digit just before it.

Answer: (C) Three

Concept: Compare the letter positions within each cluster.

1. TL – NX: $20\to 12$ ($-8$), $14\to 24$ ($+10$).
2. NF – HR: $14\to 6$ ($-8$), $8\to 18$ ($+10$); JB – DN: $10\to 2$ ($-8$), $4\to 14$ ($+10$).
3. DV – PH: $4\to 22$ ($+18$), $16\to 8$ ($-8$) – pattern differs.

Trick: Also, first letters T→N, N→H, J→D drop by 6, but D→P does not.

Answer: (D) DV - PH

Concept: Find the gaps between consecutive letters.

1. LIH: $12\to 9\to 8$ ($-3,-1$); YVU: $25\to 22\to 21$ ($-3,-1$); RON: $18\to 15\to 14$ ($-3,-1$).
2. CAY: $3\to 1\to 25$ ($-2,-2$ with wrap-around) – different.

Trick: Write the alphabet numbers once; the three matching clusters show the same gaps.

Answer: (B) CAY

Concept: Differences are perfect squares $1^2,2^2,3^2,4^2,5^2$.

1. $56+1=57$
2. $57+4=61$
3. $61+9=70$, $70+16=86$, $86+25=111$ ✓

Trick: Check from the end: $111-86=25$, $86-70=16$ → squares, so $?=70-9$.

Answer: (B) 61

Concept: Find the gaps between consecutive letters.

1. DGI: $4\to 7\to 9$ ($+3,+2$); LOQ: $12\to 15\to 17$ ($+3,+2$); UXZ: $21\to 24\to 26$ ($+3,+2$).
2. ZDE: $26\to 4\to 5$ ($+4,+1$ with wrap-around) – different.

Trick: Use EJOTY ($5,10,15,20,25$) to read letter positions fast.

Answer: (C) ZDE

Concept: Locate the two letters, then count the letters strictly between them in A–Z.

1. From the right: Q, T, R, C, M → 5th from right is M.
2. From the left: X, P, S → 3rd from left is S.
3. Between M(13) and S(19) in the alphabet: N, O, P, Q, R → $19-13-1=5$.

Trick: Letters between two positions $=$ difference $-1$.

Answer: (A) Five

Concept: Write the digits in ascending order under the original number and compare place by place.

1. Original: 3 1 8 4 6 5 7
2. Ascending: 1 3 4 5 6 7 8
3. Same place: only 6 (5th place) → one digit.

Trick: Only the digits that are already in their 'sorted' place stay unchanged – compare column-wise.

Answer: (A) One

Concept: Code $=2\times$(sum of alphabet positions).

1. PWEA: $16+23+5+1=45$, $45\times 2=90$ ✓
2. QAMT: $17+1+13+20=51$, $51\times 2=102$ ✓
3. LJCV: $12+10+3+22=47$, $47\times 2=94$.

Trick: Both codes are even and roughly double the letter sum – test $\times 2$ first.

Answer: (B) 94

Concept: Facing the centre: left = clockwise, right = anticlockwise.

1. P5 is immediate left of P6. Going right from P6, two people are skipped and P1 comes 3rd.
2. P7 sits between P4 and P5, so the order to the left of P6 is P5, P7, P4.
3. P3 between P2 and P1 fills the rest: P6, P5, P7, P4, P1, P3, P2 (clockwise).
4. From P6 going left to P4: P5 and P7 lie between → 2.

Trick: Fix P6 first and place every person relative to it.

Answer: (C) Two