RRB NTPC (Graduate & Under-Graduate) (RRB NTPC Standard)

A percentage is a comparison with a base of 100. Identify the reference quantity before calculating. For successive increases or decreases, apply the second percentage to the changed quantity. A percentage-point difference compares two percentages directly; a percentage change compares their relative sizes.

A ratio describes relative shares rather than absolute amounts. Add the ratio parts to find the value of one part, then multiply by the required share. An average distributes a total equally across observations. When combining groups of different sizes, use their totals or a weighted average.

Simple interest is calculated on the original principal each period. Compound interest adds interest to the balance, so later interest is earned on a larger base. Match the interest rate to the compounding period, and distinguish interest earned from the final amount.

Speed relates distance to time. For a train passing a pole, the distance travelled is the train length. For a train passing a platform, include both lengths. When objects move in opposite directions, add their speeds; when one catches another moving the same way, subtract their speeds.

Represent a task as one whole or a convenient number of units. A person completing it in a days works at 1/a tasks per day. Add rates for people working together; subtract a rate only if a worker or leak undoes completed work. State whether rates stay constant.

Read the labels, units and time period before extracting values. Distinguish a total from an average, and an absolute difference from a percentage difference. A graph can show numbers in thousands or percentages; convert them before combining quantities. Check whether a visual axis starts at zero.

Separate lengths, areas and volumes and identify the shape before using a formula. Draw the labelled dimensions. A diagram may not be to scale, so use stated relationships rather than visual estimates. In coordinate or algebraic work, check whether a result is physically meaningful.

Look first at differences, ratios, alternating positions and simple combinations of operations. A useful rule should explain every transition, not just the first pair. In a coding question, apply the stated transformation exactly and keep the order of operations visible.

Treat east and west as opposite horizontal movements and north and south as opposite vertical movements. Draw a small coordinate sketch for multi-step routes. For a ranking problem, distinguish position from the front from the number of people ahead or behind.

Translate a verbal condition into a short relation before combining it with other conditions. “All” describes an entire set, while “some” establishes at least one member. A possible arrangement is not necessarily the only arrangement. Test conclusions against every configuration allowed by the conditions.

Build a timeline that connects rulers, places and events instead of learning disconnected dates. Distinguish an archaeological source such as a coin or inscription from a later literary account. A source supports a particular historical claim; it does not automatically explain every feature of a period.

Use maps to connect locations, river systems and physical features. Distinguish latitude from longitude and weather from climate. For soils and crops, connect properties such as moisture retention with cultivation rather than treating the association as an unexplained fact.

Separate constitutional principles, institutions and specific provisions. Fundamental Rights concern constitutional protections; Directive Principles guide state policy. For institutions, note the function, source of authority and relationship with other bodies rather than memorising the name alone.

Distinguish production, income, saving and investment. Inflation describes a general rise in prices over time, rather than a price increase in a single item. Identify the role of an institution before matching it with an abbreviation or policy function.

Link a scientific term to the quantity or process it describes. Units help distinguish force, energy, power and pressure. In biology and chemistry, relate a named process to its inputs and outputs rather than learning only a definition.

Static revision covers relatively stable facts; current-affairs revision should preserve the event date and context. Record what happened, when it happened and which source confirmed it. A question about a historical host or winner should not be answered with a later edition’s result.