Bahrain Polytechnic Entry cheat sheet

Subject-verb agreement: a singular subject takes a singular verb; compound subjects joined by 'and' take a plural verb unless they form one idea.

Comma splice rule: two independent clauses cannot be joined by a comma alone; use a period, semicolon, or coordinating conjunction.

Pronoun case: use subject pronouns (I, he, she, they) for subjects and object pronouns (me, him, her, them) after prepositions and verbs.

Active vs passive: active voice places the doer before the verb; passive uses a form of 'be' plus past participle and often omits the doer.

Apostrophes mark possession (singular: 's; plural ending in s: s') and contractions; 'its' is possessive, 'it's' means 'it is'.

Misplaced modifiers: a descriptive phrase must sit next to the noun it describes, otherwise the sentence is ambiguous or illogical.

Parallel structure: items in a list or comparison must share the same grammatical form (all nouns, all infinitives, all gerunds).

Reading inference: a valid inference follows necessarily from stated evidence; it is not merely plausible or consistent with the passage.

Vocabulary in context: a word's meaning is fixed by surrounding clues such as contrast words ('however', 'unlike') and cause-effect signals.

Quadratic formula: for ax^2 + bx + c = 0, x = (-b ± sqrt(b^2 - 4ac)) / (2a); the discriminant b^2 - 4ac gives 0, 1, or 2 real roots.

Slope of a line through (x1,y1) and (x2,y2) is (y2 - y1)/(x2 - x1); parallel lines share slope, perpendicular slopes multiply to -1.

Percent change = (new - old) / old × 100; successive percentage changes do not simply add.

Area formulas: triangle ½bh, circle πr^2, trapezium ½(a+b)h, rectangle lw; volume of a cylinder is πr^2h.

Pythagoras: in a right triangle a^2 + b^2 = c^2, where c is the hypotenuse opposite the right angle.

Exponent rules: a^m × a^n = a^(m+n), a^m / a^n = a^(m-n), (a^m)^n = a^(mn), a^0 = 1 for a ≠ 0.

Probability of an event = favourable outcomes / total equally likely outcomes; P(not A) = 1 - P(A).

Mean = sum / count; median is the middle value of ordered data; mode is the most frequent value.

Number series: test differences first, then ratios, then alternating or two interleaved sequences before assuming a complex rule.

Odd-one-out items hinge on a single shared property (parity, prime status, letter position, category membership); identify the property that excludes exactly one item.

Syllogism rule: 'All A are B' plus 'All B are C' implies 'All A are C'; a valid conclusion must hold in every arrangement satisfying the premises.

Direction sense: track net displacement on a grid; a turn of 90° left or right changes the axis but not the distance travelled.

Analogy format A:B :: C:? requires the same relationship type (part-to-whole, function, degree, category) applied to C.

Coding-decoding: compute the letter shift numerically (A=1 … Z=26); consistent shifts indicate a Caesar-style rule.

Work-rate problems: combined rate equals the sum of individual rates; time together = 1 / (1/t1 + 1/t2).

Percentage and ratio shortcuts: increasing by 25% then decreasing by 20% returns to the original value, since 1.25 × 0.8 = 1.

RAM is volatile working memory cleared on power-off; ROM and SSD/HDD storage retain data without power.

An operating system manages hardware, files, and processes; application software performs user tasks and depends on the OS.

IPv4 addresses are 32-bit dotted decimals; a subnet mask separates network and host portions of the address.

Strong passwords combine length with mixed character classes; hashing stores a one-way digest rather than the plaintext password.

Phishing is a social-engineering attack using deceptive messages to obtain credentials; a digital certificate binds a public key to an identity.

Common file extensions map to content: .docx (document), .xlsx (spreadsheet), .pptx (presentation), .csv (comma-separated values), .pdf (fixed-layout document).

Spreadsheet absolute references use $ (e.g., $B$2) to fix a cell when a formula is copied; relative references shift with the copy.

Boolean logic: AND requires all inputs true, OR requires at least one true, NOT inverts; these underpin search queries and spreadsheet functions.

Newton's second law: F = ma; a net force produces acceleration in the direction of the force, inversely proportional to mass.

Speed = distance / time; acceleration = change in velocity / time; velocity includes direction, speed does not.

Photosynthesis: 6CO2 + 6H2O + light energy → C6H12O6 + 6O2, occurring in chloroplasts using chlorophyll.

Cell basics: the nucleus holds genetic material, mitochondria release energy via respiration, and plant cells have a cellulose cell wall.

Atomic structure: protons (positive) and neutrons (neutral) sit in the nucleus; electrons (negative) occupy shells around it; atomic number = proton count.

pH scale runs 0-14: below 7 acidic, 7 neutral, above 7 basic; each unit represents a tenfold change in hydrogen ion concentration.

States of matter: solids have fixed shape and volume, liquids fixed volume but not shape, gases neither; heating increases particle kinetic energy.

Energy forms: kinetic (motion) and potential (position) convert into each other; energy is conserved but degrades to heat through friction.