भिन्न, दशमलव और प्रतिशत रूपांतरण
Fractions, Decimals and Percentage Conversions
Bank arithmetic is really fraction arithmetic in disguise. If you can flip between a fraction, its decimal and its percentage without pausing to think, then data interpretation and approximation questions collapse into one or two clean steps. This conversion table is the most reused sheet in the whole Numerical section, so it deserves more revision time than almost any formula.
The Table You Must Know Cold
Learn each row as a single fact — fraction, decimal and percentage together — rather than converting on the spot. When 12.5% and 1/8 and 0.125 are the same object in your mind, you stop calculating and start recognising.
| Fraction | Decimal | Percentage |
|---|---|---|
| 1/2 | 0.5 | 50% |
| 1/3 | 0.333 | 33.33% |
| 1/4 | 0.25 | 25% |
| 1/5 | 0.2 | 20% |
| 1/6 | 0.1666 | 16.66% |
| 1/7 | 0.1428 | 14.28% |
| 1/8 | 0.125 | 12.5% |
| 1/9 | 0.111 | 11.11% |
| 1/11 | 0.0909 | 9.09% |
| 1/12 | 0.0833 | 8.33% |
Shortcut: Percentage as Fraction Beats Decimal Multiplication
To find 37.5% of 640, do not multiply by 0.375. Use 37.5% = 3/8, so 3/8 × 640 = 3 × 80 = 240. Fractions cancel cleanly against the number, while decimals force you to track trailing zeros and a decimal point. In a timed DI set this single habit is worth several finished questions.
Shortcut: Splitting and Flipping a Percentage
Break an awkward percentage into easy parts: 15% of 360 = 10% (36) + 5% (18) = 54, and 12% of 250 = 10% (25) + 2% (5) = 30. You can also flip the two numbers, because x% of y always equals y% of x — so 18% of 50 becomes the far easier 50% of 18 = 9.
x% of y = y% of x (e.g. 16% of 25 = 25% of 16 = 4)
Solved Examples
Example 1: 62.5% of 800 = 5/8 × 800 = 5 × 100 = 500.
Example 2: 8.33% of 1200 = 1/12 × 1200 = 100.
Example 3: 24% of 150 flipped is 150% of 24 = 24 + 12 = 36. The flip turned an awkward 24% into a one-line addition.
✗ 37.5% of 640 = 0.375 × 640 by long multiplication | ✓ 3/8 × 640 = 240 in one step
Comparing Fractions Without a Common Denominator
DI questions often ask which of several fractions is largest, and finding a common denominator wastes precious time. Use cross-multiplication on two fractions at a time: to compare 5/8 and 7/11, multiply across to get 5 × 11 = 55 against 7 × 8 = 56, so 7/11 is the larger. For a quick single-fraction sense, remember that a fraction grows when its numerator rises or its denominator falls. Keep the current winner and test it against the next fraction only, so a set of four fractions needs just three quick cross-checks rather than four full conversions.
हर प्रतिशत को भिन्न में बदलकर हल करना दशमलव गुणा से तेज़ है। 'x% of y = y% of x' नियम और प्रतिशत को टुकड़ों में बाँटना — दोनों बहुत समय बचाते हैं।
Exam Pointer — These conversions never appear as a named question, yet they power almost every DI, profit-and-loss and approximation sum in SBI Clerk. Aspirants who have this table by heart solve DI sets 30–40 seconds faster overall, and in a sectional-timed exam that saved time is often the difference between clearing the section and leaving two questions blank.
60-Second Recap
- Learn fraction–decimal–percentage triples up to 1/12 as single facts.
- Convert percentages to fractions before multiplying.
- Split percentages: 15% = 10% + 5%.
- x% of y = y% of x — flip to whichever form is easier.