Elimination Drill

If the answer must be an energy/time/speed, options whose units disagree can be crossed out without solving.

Bound the answer with anchors you know (sin 30°, pH 7, escape velocity scale). Extreme outliers are almost always decoys.

Setters hide the key inside ± sign-flips, reciprocals, or same-magnitude pairs. Spot the pair to focus your choice.

"All of the above" is correct more often than chance; "None of the above" is usually a trap. Verify two and commit.

Plug in extreme values (x → 0, m → ∞, n = 1). Only the option with the right limit behaviour can be correct.

Substitute each option back into the problem. Often faster than solving forward — especially for quadratics, log, balancing, and pH.

Probability ∈ [0, 1]. Speed ≥ 0. sin/cos ∈ [−1, 1]. pH ∈ [0, 14]. Strike any option that violates the physical or mathematical domain.

When the problem is symmetric in two variables (R₁ ↔ R₂, x ↔ y), the answer must be symmetric too. Options that break symmetry are decoys.

Plug a tidy value (x = 0, x = π/4, n = 1) into each option. Whichever simplifies to the expected number survives — the rest don't.

Apply mass, charge, momentum, or energy conservation to each option. Any violation rules the option out without solving the full problem.

Apply x → −x and compare. Odd integrals over symmetric intervals vanish; sums of an odd and an even function have mixed parity. Fast kill for identity MCQs.