CSAT Solved Papers/ 2025/Q56

2025 CSAT — Q56

Quant Logical & quantitative reasoning 2.5 marks Medium

If NO is coded as 210210, NOT is coded as 42004200 and NOTE is coded as 2100021000, then how is NOTES coded?

  1. A 399000 Answer
  2. B 420000
  3. C 440000
  4. D 630000

Worked rationale

Replace each letter by its alphabet position and read the code as the running product:

N=14, O=15, T=20, E=5, S=19.N=14,\ O=15,\ T=20,\ E=5,\ S=19.
  • NO: 14×15=21014 \times 15 = 210 ✓
  • NOT: 14×15×20=420014 \times 15 \times 20 = 4200 ✓
  • NOTE: 14×15×20×5=2100014 \times 15 \times 20 \times 5 = 21000 ✓

Each new letter multiplies the running product by its position value. So

NOTES=21000×19=399000.\text{NOTES} = 21000 \times 19 = 399000.

Answer: (a) 399000.

Why the other options miss

  • B
    reached for the wrong value: multiplies the previous code by 2020 (re-using T’s value) instead of S’s value 1919.
  • C
    an arithmetic slip: in 21000×1921000 \times 19 (e.g. 21×1921 \times 19 mis-taken as ≈21\approx 21).
  • D
    reached for the wrong value: multiplies by 3030 (a wrong position for S) — treats the letter-to-number map loosely.

Specialist insight

The code is purely arithmetic: letter →\to alphabet position →\to running product. The single required reflex is recognising the multiplicative chain from the first three codes (210,4200,21000210, 4200, 21000 each multiply by the next letter’s value), then extending by S =19=19. The decoy values all arise from picking the wrong position number for S — so confirming S’s position (1919, not 2020 or 3030) is the whole game. Verify the chain on a known code before extending: 4200/210=20=4200/210 = 20 = T’s value, which confirms the rule in one division.

The trap, in one line

The code is the running product of alphabet positions; NOTES =14⋅15⋅20⋅5⋅19=399000= 14\cdot15\cdot20\cdot5\cdot19 = 399000 (multiply by S =19=19, not 2020).

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