RRB NTPC Undergraduate CBT 1 2024 PYQs

Concept: Required speed $=\frac{\text{remaining distance}}{\text{remaining time}}$.

1. First part: $34\times 4=136\text{km}$ in 4 h.
2. Second part: 180 km at 30 km/h takes $\frac{180}{30}=6$ h.
3. Covered $316\text{km}$ in 10 h ⇒ left $843-316=527\text{km}$ in $11-10=1$ h.
4. Speed $=\frac{527}{1}=527\text{km/h}$.

Trick: With exactly 1 hour left, the speed equals the remaining distance.

Answer: (A) 527 km/hr

Concept: Let second number $=x$, first $=5x$; then $5x·x=3645$.

1. $5x^2=3645\Rightarrow x^2=729\Rightarrow x=27$.
2. First $=135$; sum $=135+27=162$.

Trick: Sum $=6x$, so the answer must be a multiple of 6 — only 162 is.

Answer: (C) 162

Concept: Take total work = LCM of days; find units done together and the remainder.

1. Total work $=\text{LCM}(9,19)=171$ units; A $=19$, B $=9$ units/day.
2. Together $=28$ units/day; in 6 days $=168$ units.
3. Left $=171-168=3$ units $=\frac{3}{171}=\frac{1}{57}$.

Trick: Fraction done $=6(\frac{1}{9}+\frac{1}{19})=\frac{168}{171}=\frac{56}{57}$, so left $=\frac{1}{57}$.

Answer: (D) $\frac{1}{57}$

Concept: If $8A=3B=6C=k$, then $A:B:C=\frac{1}{8}:\frac{1}{3}:\frac{1}{6}$.

1. Multiply by LCM 24: $A:B:C=3:8:4$; total parts $=15$.
2. Share of A $=\frac{3}{15}\times 35600=7120$.

Trick: Check the ratio: $8\times 3=3\times 8=6\times 4=24$ — all equal, so $3:8:4$ is right.

Answer: (C) ₹7,120

Concept: Mean proportional of $a$ and $b$ $=\sqrt{ab}$.

1. $\sqrt{324\times 16}=\sqrt{324}\times \sqrt{16}=18\times 4=72$.

Trick: Take square roots separately when both numbers are perfect squares.

Answer: (B) 72

Concept: Simplify the complex fraction first, then combine.

1. $1+\frac{2}{7}=\frac{9}{7}$, so $\frac{1}{9/7}=\frac{7}{9}$.
2. $\frac{5}{3}-\frac{2}{3}=1$.
3. Value $=1+\frac{7}{9}=\frac{16}{9}$.

Trick: Group like denominators ($\frac{5}{3}-\frac{2}{3}$) before anything else.

Answer: (A) $\frac{16}{9}$

Concept: Divisible by 5 ⇔ last digit 0 or 5; by 3 ⇔ digit sum divisible by 3.

1. Last digit is 5 ⇒ divisible by 5.
2. Digit sum $=4+8+1+3+5+5=26$, not divisible by 3 ⇒ not by 3, 6 or 15.
3. It is odd, so not by 6 either.

Yaad rakhein: 15 needs both 3 and 5; 6 needs both 2 and 3.

Answer: (D) 5

Concept: $\text{SI}=\frac{P\times R\times T}{100}$.

1. $\text{SI}=\frac{400\times 16\times 4.5}{100}=4\times 16\times 4.5$.
2. $=64\times 4.5=288$.

Trick: $P=400$ ⇒ SI $=4\times R\times T$ directly.

Answer: (D) 288

Concept: Average $=\frac{\text{sum}}{\text{count}}$.

1. Sum $=40+49+56+74+38=257$.
2. Average $=\frac{257}{5}=51.4\text{kg}$.

Trick: Deviation from 50: $-10-1+6+24-12=7$; $50+\frac{7}{5}=51.4$.

Answer: (C) 51.4

Concept: Compute each quantity and subtract.

1. $65\%$ of $65=\frac{65\times 65}{100}=42.25$.
2. $\frac{1}{5}$ of $55=11$.
3. Difference $=42.25-11=31.25$.

Trick: ${65}^2=4225$ (numbers ending in 5: $6\times 7=42$, then 25).

Answer: (C) 31.25

Concept: Letters common to both words share the common digits; the leftover letter takes the leftover digit.

1. DRAG → {5, 8, 2, 4}; GRAM → {4, 5, 9, 2}.
2. Common letters R, A, G ↔ common digits 5, 2, 4.
3. Left in GRAM: M ↔ 9 (and D ↔ 8).

Trick: Strike out common letters and common digits — what remains pairs up.

Answer: (B) 9

Concept: The only letter common to both words must take the only digit common to both codes.

1. EARS → {1, 3, 5, 7}; SOUP → {2, 1, 4, 6}.
2. Common letter: S; common digit: 1.
3. So S = 1.

Trick: One common letter ↔ one common digit.

Answer: (C) 1

Concept: Track each letter position separately.

1. 1st letters: T, V, X, Z, B (+2, wrapping Z → B).
2. 2nd letters: A, C, E, G, I (+2).
3. 3rd letters: W, Y, A, C, E (+2).

Trick: All three positions move $+2$; after Z comes A, so $Z+2=B$, $C+2=E$.

Answer: (C) BIE

Concept: Pick the highest and lowest numbers, then the required digits.

1. Highest $=625$ → third digit $=5$.
2. Lowest $=156$ → second digit $=5$.
3. Sum $=5+5=10$.

Trick: Compare first digits only: 6 (625) is largest, 1 (156) smallest.

Answer: (C) 10

Concept: Interchange the signs first, then apply BODMAS.

1. $19+40-8\times 2÷1$ becomes $19\times 40÷8+2-1$.
2. $19\times 40=760$; $760÷8=95$.
3. $95+2-1=96$.

Trick: Rewrite the full expression with new signs before calculating.

Answer: (A) 96

Concept: Number positions 1 (bottom) to 7 (top) and place fixed clues first.

1. No box above G ⇒ G = 7. Three between G and B ⇒ B = 3; D just above B ⇒ D = 4.
2. One between F and D ⇒ F = 2 or 6. Four between F and E: F = 2 needs E = 7 (taken) ⇒ F = 6, E = 1.
3. A above C in slots 5, 2 ⇒ A = 5, C = 2. Top to bottom: G, F, A, D, B, C, E.
4. Boxes above B: G, F, A, D = 4.

Trick: Start from the extreme box (G at top) — it fixes the rest quickly.

Answer: (A) 4

Concept: Compare each letter of the first cluster with the matching letter of the second.

1. UX-ZS: U→Z $+5$, X→S $-5$. OR-TM: $+5$, $-5$. RU-WP: $+5$, $-5$.
2. LO-QI: L→Q $+5$ but O→I $-6$.

Trick: Write positions: L=12, O=15, Q=17, I=9 — the second gap breaks the pattern.

Answer: (C) LO-QI

Concept: Each term decreases by a constant amount.

1. $121-117.9=3.1$, $117.9-114.8=3.1$, … common difference $-3.1$.
2. Next $=108.6-3.1=105.5$.

Trick: Constant difference ⇒ arithmetic progression.

Answer: (A) 105.5

Concept: Track each letter position and the number separately.

1. 1st letters P, R, T, V, X (+2); 2nd K, I, G, E, C (−2); 3rd E, H, K, N, Q (+3).
2. Numbers 17, 10, 1, ?, −23: differences −7, −9, −11, −13 ⇒ $1-11=-10$.
3. Check: $-10-13=-23$ ✓.

Trick: Differences of the numbers themselves form an AP (−7, −9, −11…).

Answer: (B) VEN −10

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

1. Original: 4 5 1 2 6 8 9; Ascending: 1 2 4 5 6 8 9.
2. Matching places: 6, 8, 9 (5th, 6th, 7th).
3. So 3 digits keep their position.

Trick: Write both numbers one under the other and tick matching columns.

Answer: (A) Three