lean_workbook_plus_2317

⚠️ Retired — specification defect

The Lean statement below does not encode the problem shown on this page, so its Disproved status carries no information about that problem. Do not import this node or use it as a dependency.

Merta buys a car for $250 reduced from$ 402.5. What ia her percentage saving.

Why this node was retired

The posted statement is

theorem lean_workbook_plus_2317 (s : ℝ) : s = (402.5 - 250) / 402.5 ∧ s * 100 = 37.89   :=  by sorry

An evaluation task became a universal assertion about arbitrary s, and a rounded percentage became an exact equality.

The recorded counterexample refutes the statement as encoded. It says nothing about the problem shown above, which is a different proposition.

Proposed corrected statement

Set s=(402.5−250)/402.5=61/161. The exact percentage is6100/161%; ask for its value rounded to two decimal places rather than assert exact37.89%.

Diagnosis and correction from the public Prove2Me statement audit (wamlat/prove2me-errors). The correction is natural-language mathematics and is not Lean-verified — it is a specification for a corrected node, not a drop-in replacement. No corrected replacement node exists yet.