KMAT flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Successive percentage change
- Two successive changes of a% and b% produce a net change of a + b + ab/100 percent. A 20% rise then 20% fall gives a net 4% fall, not zero.
- Compound interest formula
- Amount = P(1 + R/100)^T for annual compounding. For two years, compound interest exceeds simple interest by P(R/100)^2.
- Work rate rule
- If A finishes in x days and B in y days, together they finish in xy/(x + y) days. Add rates, never times.
- Downstream and upstream speeds
- Downstream speed equals boat speed plus stream speed; upstream equals boat minus stream. Boat speed is the average of the two; stream speed is half their difference.
- Combination formula
- nCr = n!/[r!(n − r)!] counts unordered selections. nCr equals nC(n − r), so choosing 2 from 10 equals choosing 8 from 10.
- Pie chart sector angle
- Each sector angle equals (component/total) × 360°. A 1% share corresponds to 3.6°, so a 25% share is a right angle.
- Percentage increase base
- Percentage increase = (new − old)/old × 100. The denominator is always the original or base value, never the new value.
- Weighted average
- Weighted average = Σ(weight × value)/Σweights. It lies between the smallest and largest values and shifts toward the group with the larger weight.
- Subject-verb agreement rule
- A singular subject takes a singular verb even when a plural phrase intervenes. 'One of the students is' is correct because the subject is 'one'.
- Correlative conjunction pairs
- Fixed pairs are 'not only...but also', 'between...and', 'neither...nor', 'either...or', 'scarcely...when', 'no sooner...than'. Mixing pairs is an error.
- Dangling modifier
- An opening participial phrase must describe the subject of the main clause. 'Walking down the road, I saw a dog' is correct; 'Walking down the road, the dog...' is dangling.
- Redundancy errors
- Expressions like 'return back', 'discuss about', 'more better', 'very unique', and 'revert back' are always wrong because one word already carries the meaning.
- Inference versus assumption
- An inference follows necessarily from stated facts; an assumption is unstated and required for the argument. Inference questions forbid outside knowledge.
- Extreme qualifier trap
- Options with 'always', 'never', 'all', or 'none' are usually wrong in RC unless the passage states them explicitly. Prefer qualified options.
- Contrast markers in RC
- Words like 'however', 'although', 'yet', and 'despite' signal a shift; the author's real position often follows the contrast, not precedes it.
- Vocabulary in context
- Substitute each option into the original sentence and check whether the passage's logic still holds. A dictionary meaning may not fit the context.
- Syllogism validity test
- A conclusion is valid only if it holds in every possible Venn diagram of the premises. One counterexample diagram makes the conclusion invalid.
- Contrapositive rule
- 'If P then Q' implies 'If not Q then not P'. The converse 'If Q then P' and inverse 'If not P then not Q' are both invalid.
- Necessary versus sufficient
- P is sufficient for Q when P implies Q. P is necessary for Q when Q implies P. Confusing the two is the most common reasoning error.
- Circular arrangement count
- n people around a circle have (n − 1)! distinct arrangements because rotations are identical. If clockwise and anticlockwise are the same, divide by 2.
- Constitution adoption dates
- India's Constitution was adopted on 26 November 1949 and came into force on 26 January 1950, the date celebrated as Republic Day.
- Fundamental Rights and DPSP
- Fundamental Rights occupy Part III, Articles 12 to 35. Directive Principles occupy Part IV, Articles 36 to 51, and are non-justiciable.
- RBI establishment
- The Reserve Bank of India was established in 1935 and nationalised in 1949. It sets the repo rate under the inflation-targeting framework.
- GDP versus GNP
- GDP measures output produced within a country's borders. GNP equals GDP plus net factor income from abroad, so it can exceed or fall below GDP.
- Inflation target in India
- The Monetary Policy Committee targets CPI inflation at 4% with a tolerance band of plus or minus 2%, giving a range of 2% to 6%.
- Heron's formula
- For sides a, b, c, let s = (a + b + c)/2. Triangle area = √[s(s − a)(s − b)(s − c)]. Useful when no height is given.
- Cone slant height
- Slant height l = √(r² + h²) for a right circular cone. Curved surface area = πrl and volume = (1/3)πr²h.
- Polygon angle sums
- Interior angles of an n-sided polygon sum to (n − 2) × 180°. Each exterior angle of a regular polygon equals 360°/n.
- Similar figure scaling
- When two similar figures have linear ratio k, their areas scale as k² and their volumes as k³. Doubling dimensions multiplies volume by eight.
- Percentage points versus percent
- A move from 20% to 25% is 5 percentage points but a 25% relative increase, because the change is divided by the original 20%.
- Stacked bar reading
- In a stacked bar chart, each component's value is the height of its own segment, not the height of the top edge above the axis.
- Profit percentage base
- Profit percentage is calculated on cost price unless the question states otherwise. Selling price = cost price × (1 + profit/100).