{"id":"cb_question_bank:bd5c0a67-f9cd-4ba7-814e-9d308088f9cb","source_id":"cb_question_bank","source_item_id":"bd5c0a67-f9cd-4ba7-814e-9d308088f9cb","external_id":null,"ibn":"05355-DC","question_id":"b8e73b5b","program":"SAT","module":"math","domain_code":"H","domain":"Algebra","skill_code":"H.E.","skill":"Linear inequalities in one or two variables","difficulty":"H","score_band":6,"answer_type":"mcq","answer_source":"key","layout_warning":null,"form_id":null,"module_number":null,"position":null,"stem":"Ken is working this summer as part of a crew on a farm. He earned $8 per hour for the first 10 hours he worked this week. Because of his performance, his crew leader raised his salary to $10 per hour for the rest of the week. Ken saves 90% of his earnings from each week. What is the least number of hours he must work the rest of the week to save at least $270 for the week?","stimulus":"","stimulus_html":null,"stem_html":"<p class=\"stem_paragraph \">Ken is working this summer as part of a crew on a farm. He earned $8&nbsp;per&nbsp;hour for the first 10&nbsp;hours he worked this week. Because of his performance, his crew leader raised his salary to $10&nbsp;per&nbsp;hour for the rest of the week. Ken saves 90% of his earnings from each week. What is the least number of hours he must work the rest of the week to save at least $270 for the&nbsp;week?</p>\n","rationale_html":"<p>Choice C is correct. Ken earned $8 per hour for the first 10 hours he worked, so he earned a total of $80 for the first 10 hours he worked. For the rest of the week, Ken was paid at the rate of $10 per hour. Let <span class=\"italic\">x</span> be the number of hours he will work for the rest of the week. The total of Ken’s earnings, in dollars, for the week will be <span class=\"math-container\"><img align=\"middle\" role=\"math\" class=\"math-img\" src=\"/api/assets/bb5f65446fc73730c60ca5ffdf25d7fc367376e6b98db69955239abc9792bc63\" alt=\"10 x plus 80\"></span>. He saves 90% of his earnings each week, so this week he will save <span class=\"math-container\"><img align=\"middle\" role=\"math\" class=\"math-img\" src=\"/api/assets/cfea17e2b8c11d216685c1f8b103882a10cf580449892c7b3f48c0e5fc3448f1\" alt=\"0 point 9 times, open parenthesis, 10 x plus 80, close parenthesis\"></span> dollars. The inequality <span class=\"math-container\"><img align=\"middle\" role=\"math\" class=\"math-img\" src=\"/api/assets/ff6902576165db183b3ff2ec6761a0e8b242829ccf10fc0dbc2bd9b8d1cbbd18\" alt=\"0 point 9 times, open parenthesis, 10 x plus 80, close parenthesis, is greater than or equal to 270\"></span> represents the condition that he will save at least $270 for the week. Factoring 10 out of the expression <span class=\"math-container\"><img align=\"middle\" role=\"math\" class=\"math-img\" src=\"/api/assets/bb5f65446fc73730c60ca5ffdf25d7fc367376e6b98db69955239abc9792bc63\" alt=\"10 x plus 80\"></span> gives <span class=\"math-container\"><img align=\"middle\" role=\"math\" class=\"math-img\" src=\"/api/assets/2c59502fa3631a6b314e28a31971a7541326572061931ee31fb63fb83e4e8c9a\" alt=\"10 times, open parenthesis, x plus 8, close parenthesis\"></span>. The product of 10 and 0.9 is 9, so the inequality can be rewritten as <span class=\"math-container\"><img align=\"middle\" role=\"math\" class=\"math-img\" src=\"/api/assets/db5ca8ef2f91c31e62002269fbaedf5308b7dabab1e4d9f8b22e43b4eccfe1a8\" alt=\"9 times, open parenthesis, x plus 8, close parenthesis, is greater than or equal to 270\"></span>. Dividing both sides of this inequality by 9 yields <span class=\"math-container\"><img align=\"middle\" role=\"math\" class=\"math-img\" src=\"/api/assets/b2f8d9f98dc31f916a07bfc91b93c8450ea8adb1e5e7128a86e1d54b4f2fd530\" alt=\"x plus 8, is greater than or equal to 30\"></span>, so <span class=\"math-container\"><img align=\"middle\" role=\"math\" class=\"math-img\" src=\"/api/assets/0e9f49db7c3260dd7873c765397627728134db06ddb724208aeed2d668d53e04\" alt=\"x is greater than or equal to 22\"></span>. Therefore, the least number of hours Ken must work the rest of the week to save at least $270 for the week is 22.</p><p>Choices A and B are incorrect because Ken can save $270 by working fewer hours than 38 or 33 for the rest of the week. Choice D is incorrect. If Ken worked 16 hours for the rest of the week, his total earnings for the week will be <span class=\"math-container\"><img align=\"middle\" role=\"math\" class=\"math-img\" src=\"/api/assets/2c899cc8f8bd5eee1aa9e3f190b2bf2e474fdf08967c5557358d485ed6950414\" alt=\"80 dollars plus 160 dollars, equals 240 dollars\"></span>, which is less than $270. Since he saves only 90% of his earnings each week, he would save even less than $240 for the week.</p><p></p>\n","correct_answer":["C"],"has_media":true,"has_mathml":false,"has_table":false,"source_created_at":"2023-08-02T20:25:59.629000+00:00","source_updated_at":"2023-08-02T20:25:59.629000+00:00","options":[{"label":"A","content_html":"<p class=\"choice_paragraph \">38</p>\n","ord":0},{"label":"B","content_html":"<p class=\"choice_paragraph \">33</p>\n","ord":1},{"label":"C","content_html":"<p class=\"choice_paragraph \">22</p>\n","ord":2},{"label":"D","content_html":"<p class=\"choice_paragraph \">16</p>\n","ord":3}],"attribution":{"source_id":"cb_question_bank","source_name":"College Board digital SAT question bank (community dump)","rights_holder":"College Board","canonical_url":"https://satsuitequestionbank.collegeboard.org/","retrieved_from":"https://raw.githubusercontent.com/mdn522/sat-question-bank/main/data/cb-digital-questions.json","attribution":"SAT practice questions © College Board, from the official SAT Suite Question Bank. Retrieved via the community dump at github.com/mdn522/sat-question-bank.","disclaimer":"SAT® and PSAT/NMSQT® are trademarks registered by the College Board, which is not affiliated with, does not sponsor, and does not endorse this project.","license":"College Board copyright; source repository carries no licence. Local use only.","redistributable":false,"item_count":2017}}