{"id":"cb_practice_pdf:t4-math-m1-q17","source_id":"cb_practice_pdf","source_item_id":"t4-math-m1-q17","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":null,"form_id":"cb_practice_pdf:test-4","module_number":1,"position":17,"stem":"For a certain rectangular region, the ratio of its length to its width is 35 to 10. If the width of the rectangular region increases by 7 units, how must the length change to maintain this ratio?","stimulus":"","stimulus_html":null,"stem_html":"<p>For a certain rectangular region, the ratio of its length to its width is 35 to 10. If the width of the rectangular region increases by 7 units, how must the length change to maintain this ratio?</p>","rationale_html":"<p>Choice B is correct. It’s given that the ratio of the rectangular region’s length to its  length=35 =35 width is 35 to 10. This can be written as a proportion: , or . This width 10 w 10 = = proportion can be rewritten as 10 35w, or 3.5w. If the width of the rectangular region increases by 7, then the length will increase by some number  x in order to maintain this ratio. The value of x can be found by replacing with + +  + = ( +) x and w with w 7 in the equation, which gives 3.5x 7 .w This  + = + equation can be rewritten using the distributive property as 3.5x 24w.5. 38 SAT PRACTICE TEST #4 ANSWER EXPLANATIONS SAT ANSWER EXPLANATIONS nnn MATH: MODULE 1 = Since 3.5w, the right-hand side of this equation can be rewritten by   + = + = substituting for 3.5w, which gives x 24.5, or x 24.5. Therefore, if the width of the rectangular region increases by 7 units, the length must increase by 24.5 units in order to maintain the given ratio. Choice A is incorrect. If the width of the rectangular region increases, the length must also increase, not decrease. Choice C is incorrect. If the width of the rectangular region increases, the length must also increase, not decrease. Choice D is incorrect. Since the ratio of the length to the width of the rectangular region is 35 to 10, if the width of the rectangular region increases by 7 units, the length would have to increase by a proportional amount, which would have to be greater than 7 units.</p>","correct_answer":["B"],"has_media":false,"has_mathml":false,"has_table":false,"source_created_at":null,"source_updated_at":null,"options":[{"label":"A","content_html":"<p>It must decrease by 24.5 units.</p>","ord":0},{"label":"B","content_html":"<p>It must increase by 24.5 units.</p>","ord":1},{"label":"C","content_html":"<p>It must decrease by 7 units.</p>","ord":2},{"label":"D","content_html":"<p>It must increase by 7 units.</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}}