Percentage Questions for SBI CLERK

What is Percentage

Percentage means 'per hundred'. When we say 40%, we mean 40 out of every 100. It is a way to express a fraction or ratio with denominator 100. Think of it as a universal language to compare any two quantities on a common scale of 100.

• Percent symbol % means divide by 100. So 40% = 40/100 = 0.40
• To convert fraction to percent: multiply by 100. Example: 3/4 = 75%
• To convert percent to fraction: divide by 100. Example: 12.5% = 12.5/100 = 1/8
• Memorise fraction-percent equivalents up to 1/12 to save time in exam

Percentage Increase and Decrease

These are the most common question types. Percentage increase or decrease is always calculated on the ORIGINAL (base) value, not the new value. A very common trap is using the final value as the base instead of the starting value.

• Percentage Increase = (Increase / Original) x 100
• Percentage Decrease = (Decrease / Original) x 100
• If a value increases by R%, new value = Original x (1 + R/100)
• If a value decreases by R%, new value = Original x (1 - R/100)
• A 20% increase followed by a 20% decrease does NOT give back original — net is a 4% decrease

Reverse Percentage (Finding Original Value)

In SBI Clerk, questions often give the final value after a percentage change and ask for the original. This is called reverse percentage or back-calculation. Many aspirants panic here, but it is straightforward once you remember the multiplier approach.

• If final value is given after X% increase, original = Final / (1 + X/100)
• If final value is given after X% decrease, original = Final / (1 - X/100)
• After 20% increase: if new value = 600, original = 600/1.20 = 500
• Quick trick: if something is 120% of original, original is 100/120 of new value = 5/6 of new value

Key Fraction-Percent Conversions to Memorise

In SBI Clerk you get 60 seconds per question. The fastest way to solve percentage questions is to convert percentages to fractions mentally. This avoids long division. Treat this table like your multiplication table — must be at fingertips.

• 1/2 = 50%, 1/3 = 33.33%, 1/4 = 25%, 1/5 = 20%
• 1/6 = 16.67%, 1/7 = 14.28%, 1/8 = 12.5%, 1/9 = 11.11%, 1/10 = 10%
• 1/11 = 9.09%, 1/12 = 8.33%
• 2/3 = 66.67%, 3/4 = 75%, 3/5 = 60%, 5/6 = 83.33%

Percentage in Data Interpretation

In SBI Clerk Mains, DI sets (bar graphs, pie charts, tables) heavily test percentage concepts. Questions ask: percentage share, percentage increase over previous year, what percent is one category of total, etc. The calculation is the same — only the data comes from a table or graph instead of a text problem.

• Pie chart angle = (% share / 100) x 360 degrees
• When comparing two years in bar chart, always use the earlier year as base for % change
• In table DI, read the question carefully — some ask % of row total, others ask % of column total
• Approximate boldly in DI — options are usually far apart enough to allow rounding

• Using final value as base instead of original value when calculating % increase or decrease. Always go back to the original/starting value as denominator.
• Thinking that a 20% rise followed by 20% fall returns to original. It does not — net result is always a loss equal to (R squared / 100) percent.
• In reverse percentage, adding/subtracting the percent from the final value instead of dividing. Example: if 120 is after 20% rise, original is NOT 120 - 20 = 100 by luck but should be 120/1.20 = 100 — coincidence here confuses students on other numbers.
• Confusing 'A is what percent of B' with 'A is what percent more than B'. The first is (A/B)x100, the second is ((A-B)/B)x100.
• In pie charts, finding percent share of a category correctly but then computing the wrong final value because they use wrong total from the question.

• BORN rule for % change: Base is Old, Result is New. Always divide by the OLD/original value.
• Successive change formula shortcut: think of it as two people sharing profit. a + b + ab/100. The ab/100 term is always a bonus or penalty on top. For two increases it adds, for one increase one decrease it subtracts.
• Fraction table as a song pattern: 1/2, 1/4, 1/8 are 50, 25, 12.5 — each halves the previous. 1/3, 1/6, 1/9, 1/12 follow 33.33, 16.67, 11.11, 8.33 — each third less.
• Reverse percentage = always DIVIDE by the multiplier, never subtract. Think: you are undoing the change, so undo means divide.

• SBI Clerk Prelims has 20 Quant questions in 20 minutes. Pure percentage questions (2-3) are among the easiest marks — solve them in under 45 seconds each using fraction shortcuts.
• In SBI Clerk Mains DI sets (which carry heavy marks), nearly every question uses percentage. Spending 5 minutes to revise fraction-percent equivalents the night before can save 4-5 marks.
• Questions often combine percentage with ratio: 'A's salary is 25% more than B. Find ratio of their salaries.' Convert 25% more = multiply by 5/4, so A:B = 5:4. This hybrid type is very common.
• Expected difficulty in Prelims: easy to moderate. Watch for successive percentage change questions — these are moderate and often act as differentiators between candidates.
• In Mains, percentage questions inside DI sets often involve large numbers. Practice quick approximation: round to nearest 5 or 10 and check which option is closest rather than computing exactly.