How we verify every question
Test-prep sites are full of questions with the wrong answer marked correct. We built this one so that can’t happen: every answer is computed, never hand-keyed.
1The data is generated, not copied
Each question is produced by a deterministic engine: it builds the table, chart or scenario from scratch with its own numbers. Nothing is scraped from a real test, so every item is original practice content.
2The answer is computed from that data — never typed in
There is no stored answer key written by a person. The correct answer is calculated from the question's own data every time, so a mistyped key simply cannot exist. This is the rule we never break.
3Wrong options are named mistakes, on purpose
Each wrong option is built from a specific, named error — for example, using the new value as the base of a percentage change. That is why feedback can tell you what went wrong, not just that something did.
4Every item passes automated quality gates before it publishes
Before a question can go live it runs a battery of checks: the answer is uniquely correct, the wrong options are genuinely wrong, the numbers are clean, and the difficulty is computed from the item itself. Anything that fails a gate is withheld, not forced through.
5The worked solution comes from the same source
The step-by-step explanation is generated from the exact data and calculation used to produce the answer — so the working you read is the working the engine did, not a separate write-up that could drift out of sync.
The same discipline applies to your result: see how scoring works for raw scores, named weak areas and honestly labelled percentiles, or read more about who builds this.