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RBI JE study materials
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RBI JE: Quantitative Aptitude

RBI JE · Work through your exam, one topic at a time.

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Quantitative Aptitude

Quantitative Aptitude

RBI JE quantitative aptitude covers arithmetic, mensuration, number series, and data interpretation. The paper rewards formula recall and approximation; calculators are not allowed.

Core rules

  • Percentage change: successive changes of a% and b% give net a + b + ab/100.
  • SI: I = PRT/100. CI: A = P(1 + r/100)^t; for two years the CI–SI difference is P(r/100)².
  • Time and work: use rates (1/a + 1/b); work done = rate × time.
  • Speed: distance = speed × time; for same distance, time is inversely proportional to speed.
  • Mensuration: cylinder volume πr²h; sphere 4/3πr³; rectangle area lb; triangle ½bh.

Worked example

A sum becomes double in 8 years at simple interest. Find the annual rate. Reasoning: doubling means SI earned = P. So P = P × R × 8/100 → R = 100/8 = 12.5% per annum. Note: the same doubling period under CI would give a different rate because interest earns interest.

Data interpretation

Read units and labels first; compute only the required value; use percentage-point difference for rates, not percentage change. For ratios, cancel common factors before multiplying.

Traps

Confusing CI–SI difference formula applies for 2 years (for 3 years it differs); applying successive percentage as simple addition; mixing SI and CI; using diameter as radius; forgetting to convert minutes to hours.