Percentage and Ratio Questions for IBPS RRB CLERK

Percentage Basics

Percent means per hundred. Think of it as slicing any quantity into 100 equal parts and counting how many parts you have. The key skill is converting between fractions, decimals, and percentages quickly — this saves 20-30 seconds per question in the exam.

• Percent to fraction: X% = X/100
• Fraction to percent: a/b = (a/b) x 100
• Percentage of a number: P% of N = (P x N) / 100
• If A is P% more than B, then A = B x (1 + P/100)
• If A is P% less than B, then A = B x (1 - P/100)
• Percentage change = (Change / Original) x 100

Important Fraction-Percentage Table (Memorise These)

IBPS RRB questions often use fractions that map to clean percentages. Knowing these by heart means you skip all calculation and directly mark the answer. This is your speed weapon.

• 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%
• Tip: If you know 1/n, just multiply numerator to get other fractions

Ratio Basics

A ratio compares two quantities of the same kind. Think of ratio as a recipe — if cement to sand is 1:3, for every 1 bag of cement you need 3 bags of sand. The total parts = 1+3 = 4. Ratio questions in IBPS RRB mostly appear as simple division into parts, proportion problems, or combined with percentage.

• Ratio a:b means a/(a+b) is the share of the first and b/(a+b) is the share of the second
• If A:B = m:n and total = T, then A = (m/(m+n)) x T
• Equivalent ratios: a:b = ka:kb for any k
• Compounded ratio of a:b and c:d is ac:bd
• If A:B = 2:3 and B:C = 4:5, find A:C by making B equal — A:B:C = 8:12:15

Percentage and Ratio Combined

The most common IBPS RRB question type mixes both concepts. For example: ratio changes when one part increases by some percent, or express one part of a ratio as a percentage of the total. The trick is to assign actual numbers using the ratio, then apply percentage on those numbers.

• Assign the ratio value as actual numbers first (e.g., if ratio 3:5, let them be 3x and 5x)
• Apply percentage change on the variable, then re-solve
• To express ratio as percent: a:b means a is (a/(a+b)) x 100% of total
• Ratio 3:7 means first quantity is 30% of total (3/10 x 100)

• Using new value instead of original value in the denominator for percentage change — always divide by original (old) value.
• In ratio questions, forgetting to add all parts before dividing — if ratio is 2:3:5, total parts = 10, not 5 or 3.
• Confusing percent more than with percent of — if A is 20% more than B, A = 1.2B, not A = 0.2B.
• When combining ratios like A:B and B:C, not equalising the B term using LCM — directly writing wrong combined ratio.
• In reverse percentage questions, dividing by the percentage instead of (1 + P/100) — classic trap in easy-looking questions.

• POCOW for percentage change: Put Old in the Cow (denominator) — Old value always goes below in % change formula.
• SALT for ratio sharing: Sum All parts, Locate your part, Then multiply by Total.
• Fraction table trick: 1/8 = 12.5, so 3/8 = 37.5 and 5/8 = 62.5 — just multiply 12.5 by numerator.
• Anchor number trick: Always assign ratio values as actual numbers (3x, 5x etc.) before doing any percent calculation — never work with ratios directly when percentages are involved.

• In IBPS RRB Office Assistant Quant, 1-2 standalone percentage questions and 1-2 ratio questions appear almost every year. DI sets also require percentage calculation indirectly.
• Questions are mostly of easy-moderate level — straightforward percentage of a number, dividing in ratio, or one-step percentage change. Rarely tricky two-step problems.
• Time target: Solve each percentage or ratio question in under 60 seconds. If it takes longer, skip and return — do not let one question eat your time.
• Fraction-to-percentage conversions appear disguised — a question might say 2/5 of a value equals what percent of total. Memorising the fraction table directly gives answer without pen.
• In recent IBPS RRB exams, combined questions like income ratio changing after a percentage hike have appeared — practice the assign-and-apply method to handle these in under 90 seconds.