DSTA Entrance Examination flashcards
DSTA Entrance Examination · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Cannot Say response
- A true/false/cannot-say answer used when the passage neither confirms nor contradicts the statement. Outside knowledge and plausibility must not be used to decide.
- Converse error
- Wrongly reversing a conditional. 'All A are B' does not imply 'All B are A'; only the contrapositive, 'all non-B are non-A', is valid.
- Contrapositive
- The logically equivalent form of a conditional obtained by negating and swapping both parts. 'If P then Q' becomes 'if not Q then not P'.
- Reverse percentage
- Recovering an original amount after a percentage change by dividing, not multiplying. A price of 85 after a 15% discount means the original was 85 divided by 0.85.
- Successive percentage change
- Combined changes are found by multiplying factors, not adding percentages. A 10% rise then a 25% rise gives 1.10 times 1.25, a 37.5% increase.
- Weighted average
- The sum of each value multiplied by its weight, divided by the sum of the weights. With equal weights it reduces to the ordinary arithmetic mean.
- Average speed round trip
- For equal distances travelled at speeds a and b, average speed is 2ab divided by (a plus b). It is never the simple mean of the two speeds.
- Combined work rate
- Rates add when workers act together. If A needs a days and B needs b days, together they finish in ab divided by (a plus b) days.
- Compound interest formula
- Amount equals principal times (1 plus the rate per period) raised to the number of periods. Interest earned is that amount minus the principal.
- Interleaved number series
- A sequence built from two alternating sub-sequences, one in odd positions and one in even positions. Check each sub-sequence separately for its own rule.
- Negation of all
- The logical opposite of 'all A are B' is 'at least one A is not B'. It is not 'no A are B', which is a much stronger claim.
- Conditional truth table
- A statement 'if P then Q' is false only when P is true and Q is false. Every other combination, including P false, makes it true.
- Lever moment balance
- A lever balances when force times distance from the pivot is equal on both sides. A longer effort arm therefore needs less force.
- Mechanical advantage of lever
- Effort arm length divided by load arm length. A value above one means the lever multiplies the applied force.
- Movable pulley advantage
- A movable pulley supported by n rope segments has mechanical advantage n. A single fixed pulley only changes direction, with advantage one.
- Meshed gear direction
- Two meshing gears rotate in opposite directions. Their speed ratio equals the inverse ratio of their tooth counts.
- Crossed belt drive
- A crossed belt makes the driven pulley rotate in the opposite direction to the driver. An open belt keeps both turning the same way.
- Pressure formula
- Pressure equals force divided by area. The same force over a smaller area gives higher pressure, which explains why sharp edges cut.
- Floating condition
- An object floats in a fluid when its density is lower than the fluid's density. Density equals mass divided by volume.
- Cube net adjacency
- When a net is folded, faces that share an edge on the net share an edge on the cube. Opposite faces never touch and are separated by one face.
- Mirror image reversal
- A plane mirror reverses the axis perpendicular to its surface. Left and right swap relative to the viewer, but top and bottom do not.
- Misleading chart baseline
- A bar chart whose vertical axis starts above zero exaggerates differences. Compare actual values, not bar heights, before drawing conclusions.
- Break-even units
- Fixed cost divided by the difference between unit price and unit variable cost. Below this volume the operation makes a loss.
- Ratio share of total
- In a ratio of 3 to 2, the larger group is three fifths of the total. Each term is divided by the sum of all terms.
- Estimation by elimination
- Round figures to two significant figures to discard clearly wrong options. Compute exactly only when two remaining options are close.
- Unit harmonisation
- Converting every figure in a table to one unit before adding or ranking. Mixing thousands and millions is the most common data-interpretation error.
- Escalation threshold
- The point where an issue exceeds your authority or expertise and must be raised to a responsible person. Safety and legal risks lower this threshold.
- Raising a colleague's error
- The effective sequence is to raise the issue directly and privately with the colleague first, then escalate if it remains unresolved and affects output.
- Insufficient information response
- When a task lacks needed detail, the effective action is to ask the relevant person or check the source, not to guess and proceed silently.
- Consistency in work-style items
- Similar self-description items are compared for contradiction. Answering honestly and consistently matters more than selecting the socially ideal trait each time.
- Process over outcome
- In ethical judgement items, a rule breach taken to save time ranks low even when the result is good. The standard is the required process.
- Word-in-context test
- Substitute each option into the sentence and keep the one preserving the sentence's logic. Formal-sounding options that break the meaning are wrong.