{"id":"cb_practice_pdf:t7-math-m1-q19","source_id":"cb_practice_pdf","source_item_id":"t7-math-m1-q19","external_id":null,"ibn":null,"question_id":null,"program":"SAT","module":"math","domain_code":null,"domain":null,"skill_code":null,"skill":null,"difficulty":null,"score_band":null,"answer_type":"mcq","answer_source":"rationale","layout_warning":"Part of this question was typeset outside the text flow — a fraction, subscript or similar — and PDF extraction re-inserted it in the wrong place. The wording is reliable; the symbols may be out of order.","form_id":"cb_practice_pdf:test-7","module_number":1,"position":19,"stem":"12/n − 2/t = − 2/w The given equation relates the variables n, t, and w, > 0 > 0 > where n, t, and w t. Which expression is equivalent to n? 12tw","stimulus":"","stimulus_html":null,"stem_html":"<p>12/n − 2/t = − 2/w The given equation relates the variables n, t, and w, &gt; 0 &gt; 0 &gt; where n, t, and w t. Which expression is equivalent to n? 12tw</p>","rationale_html":"<p>2 Choice D is correct. Adding to each side of the given equation yields 12 2 2 t =- + . The fractions on the right side of this equation have a common n w t 12 2 2 = w- t denominator of tw; therefore, the equation can be written as , or 12 = 2 w -2 t , which is equivalent to 12 = 2 ^w - th. Dividing each si n de o t f w this t w equation n tw n tw 6=w - t - by 2 yields . Since n, t, w, and w t are all positive quantities, taking the n tw 6=w - t reciprocal of each side of the equation yields an equivalent equation: n tw n= tw =6tw - . Multiplying each side of this equation by 6 yields n - . 6 w t w t Choice A is incorrect and may result from conceptual or calculation errors. Choice B is incorrect and may result from conceptual or calculation errors. 1 Choice C is incorrect. This is equivalent to rather than n. n</p>","correct_answer":["D"],"has_media":false,"has_mathml":false,"has_table":false,"source_created_at":null,"source_updated_at":null,"options":[{"label":"A","content_html":"<p>6(t−w)</p>","ord":0},{"label":"B","content_html":"","ord":1},{"label":"C","content_html":"<p>(w−t)/6tw</p>","ord":2},{"label":"D","content_html":"<p>6tw/(w−t)</p>","ord":3}],"attribution":{"source_id":"cb_practice_pdf","source_name":"College Board full-length SAT practice tests (PDF)","rights_holder":"College Board","canonical_url":"https://satsuite.collegeboard.org/practice/practice-tests/paper","retrieved_from":"https://satsuite.collegeboard.org/practice/practice-tests/paper","attribution":"Full-length SAT practice tests 4–11 © College Board, published free at satsuite.collegeboard.org.","disclaimer":"Extracted from PDF layout: equations, figures and tables do not survive intact. Use the original PDFs for anything the text renders poorly. SAT® is a trademark registered by the College Board, which is not affiliated with and does not endorse this project.","license":"College Board copyright. Free to download; not licensed for redistribution.","redistributable":false,"item_count":905}}