Percentage Questions for IBPS CLERK

Core Concept: What is a Percentage?

Percentage simply means 'per hundred'. When you say 40%, you mean 40 out of every 100. It is a way to express a fraction with denominator 100. The key skill in IBPS Clerk is converting between fractions, decimals, and percentages instantly — this saves 20-30 seconds per question.

• x% = x/100 (always)
• To convert fraction to percent: multiply by 100
• To convert percent to decimal: divide by 100 (e.g., 35% = 0.35)
• Percentage of a number: x% of N = (x/100) x N
• Memorise fraction-to-percent table up to 1/12 for speed

Percentage Increase and Decrease

These are the most common question types. A value goes up or down and you need to find the new value or the original value. Remember: increase and decrease are always calculated on the ORIGINAL (old) value, not the new one. This is the single biggest trap in this topic.

• New value after x% increase: New = Old x (1 + x/100)
• New value after x% decrease: New = Old x (1 - x/100)
• To find original: Original = New Value / (1 + x/100) for increase
• If a value increases by x% then decreases by x%, net change is NOT zero — it is a net loss of (x squared)/100 percent
• Successive changes of a% then b%: Net % = a + b + (a x b)/100

Population and Expenditure Problems

IBPS Clerk frequently gives word problems where population grows/falls by a percentage each year, or where price and consumption change and you must find the effect on expenditure. These look complicated but always reduce to the same successive percentage formula.

• Population after n years = P x (1 + r/100) raised to n
• If price rises by x%, to keep expenditure same, consumption must fall by x/(100+x) x 100 percent
• If price falls by x%, consumption can rise by x/(100-x) x 100 percent to keep expenditure same
• Expenditure = Price x Consumption — any % change question on these three uses the successive change formula

Key Fraction-to-Percentage Conversions (Speed Table)

In IBPS Clerk, time is tight. Memorising these conversions lets you avoid long division and solve questions in under 30 seconds. Think of this table as your mental calculator upgrade.

• 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%, 2/5 = 40%, 3/5 = 60%, 4/5 = 80%
• Reverse use: 37.5% = 3/8, 62.5% = 5/8, 87.5% = 7/8

• Calculating percentage change on the NEW value instead of the OLD value — always use original as base
• Thinking that x% increase followed by x% decrease returns to original — it always gives a net loss of (x squared)/100 percent
• In population problems, applying simple interest logic instead of compound — use the power formula for multi-year growth
• Confusing 'A is 20% more than B' with 'B is 20% less than A' — they are NOT the same. If A is 20% more than B, then B is 16.67% less than A
• In DI questions, finding percentage of a percentage — for example finding 30% of the 40% share — forgetting to multiply the fractions correctly

• OBIC rule for percentage change: Old is Base, Increase or decrease on Old, Compare to Old. Always anchor to OLD.
• For price-consumption problems remember the phrase RISE then CUT LESS: if price rises by x, you cut by less than x to balance. The cut formula x/(100+x) always gives a smaller number than x.
• Successive change shortcut memory hook: AB formula — a + b + ab/100. Remember it as 'Add both, then Add their Product divided by 100'.
• Fraction table memory trick using halves: 1/2=50, half of that 1/4=25, half again 1/8=12.5. For thirds: 1/3=33.33, 1/6=16.67, 1/12=8.33 — each is half the previous.

• IBPS Clerk typically has 2-3 direct percentage questions plus 4-6 more where percentage is embedded in Profit-Loss or DI sets. Mastering this topic multiplies your score across subjects.
• Questions are usually one or two steps — no lengthy chains. If your calculation is going beyond 3 steps, re-read the question because you may be overcomplicating it.
• DI sets in Prelims often ask percentage share or percentage change between two years — practice reading bar graphs and pie charts with this lens specifically.
• Use the 10% shortcut in the exam hall: find 10% first, then build up (e.g., 35% = 30% + 5% = 3x10% + half of 10%). This avoids long multiplication under pressure.
• In the actual exam, percentage questions appear in the first half of the quant section. Aim to solve each in under 45 seconds to bank time for Simplification and Series.