{"id":"cb_question_bank:02672cb2-7340-4344-8dc8-257d5159823b","source_id":"cb_question_bank","source_item_id":"02672cb2-7340-4344-8dc8-257d5159823b","external_id":"83c4d031-e8f1-4415-8c6c-33d11d65e85b","ibn":null,"question_id":"3008cfc3","program":"SAT","module":"math","domain_code":"H","domain":"Algebra","skill_code":"H.C.","skill":"Linear equations in two variables","difficulty":"H","score_band":7,"answer_type":"spr","answer_source":"key","layout_warning":null,"form_id":null,"module_number":null,"position":null,"stem":"x y k 13 k plus 7 negative 15 The table gives the coordinates of two points on a line in the xy -plane. The y -intercept of the line is left parenthesis k minus 5 comma b right parenthesis , where k and b are constants. What is the value of b ?","stimulus":"","stimulus_html":null,"stem_html":"<figure class=\"table\"><figure class=\"table\"><figure class=\"table\"><figure class=\"table\"><table border=\"1\">\n<tbody>\n<tr>\n<th style=\"width: 47.7376%; text-align: center;\" scope=\"col\"><math alttext=\"x\"><mi>x</mi>\n</math></th>\n<th style=\"width: 47.7376%; text-align: center;\" scope=\"col\"><math alttext=\"y\"><mi>y</mi>\n</math></th>\n</tr>\n<tr>\n<td style=\"width: 47.7376%; text-align: center;\"><math alttext=\"k\"><mi>k</mi>\n</math></td>\n<td style=\"width: 47.7376%; text-align: center;\"><math alttext=\"13\"><mn>13</mn>\n</math></td>\n</tr>\n<tr>\n<td style=\"width: 47.7376%; text-align: center;\"><math alttext=\"k plus 7\"><mrow>\n\t<mi>k</mi>\n\t<mo>+</mo>\n\t<mn>7</mn>\n</mrow>\n</math></td>\n<td style=\"width: 47.7376%; text-align: center;\"><math alttext=\"negative 15\"><mo>-</mo><mn>15</mn>\n</math></td>\n</tr>\n</tbody>\n</table></figure></figure></figure></figure>\n<p style=\"text-align: left;\">The table gives the coordinates of two points on a line in the <em>xy</em>-plane. The <em>y</em>-intercept of the line is <math alttext=\"left parenthesis k minus 5 comma b right parenthesis\"><mfenced><mrow><mi>k</mi><mo>-</mo><mrow><mn>5</mn></mrow><mo>,</mo><mi>b</mi></mrow></mfenced></math>, where <math alttext=\"k\"><mi>k</mi>\n</math> and <math alttext=\"b\"><mi>b</mi>\n</math> are constants. What is the value of <math alttext=\"b\"><mi>b</mi>\n</math>?</p>","rationale_html":"<p style=\"text-align: left;\">The correct answer is <math alttext=\"33\"><mn>33</mn>\n</math>. It’s given in the table that the coordinates of two points on a line in the <em>xy</em>-plane are <math alttext=\"left parenthesis k comma 13 right parenthesis\"><mo>(</mo><mi>k</mi><mo>,</mo><mn>13</mn><mo>)</mo></math> and <math alttext=\"left parenthesis k plus 7 comma negative 15 right parenthesis\"><mo>(</mo><mi>k</mi><mo>+</mo><mn>7</mn><mo>,</mo><mo>-</mo><mn>15</mn><mo>)</mo></math>. The <em>y</em>-intercept is another point on the line. The slope computed using any pair of points from the line will be the same. The slope of a line, <math alttext=\"m\"><mi>m</mi>\n</math>, between any two points, <math alttext=\"left parenthesis x 1 comma y 1 right parenthesis\"><mfenced><mrow><msub><mi>x</mi><mn>1</mn></msub><mo>,</mo><msub><mi>y</mi><mn>1</mn></msub></mrow></mfenced></math> and <math alttext=\"left parenthesis x 2 comma y 2 right parenthesis\"><mfenced><mrow><msub><mi>x</mi><mn>2</mn></msub><mo>,</mo><msub><mi>y</mi><mn>2</mn></msub></mrow></mfenced></math>, on the line can be calculated using the slope formula, <math alttext=\"m equals StartFraction left parenthesis y 2 minus y 1 right parenthesis Over left parenthesis x 2 minus x 1 right parenthesis EndFraction\"><mi>m</mi><mo>=</mo><mfrac><mfenced><mrow><msub><mi>y</mi><mn>2</mn></msub><mo>-</mo><msub><mi>y</mi><mn>1</mn></msub></mrow></mfenced><mfenced><mrow><msub><mi>x</mi><mn>2</mn></msub><mo>-</mo><msub><mi>x</mi><mn>1</mn></msub></mrow></mfenced></mfrac></math>. It follows that the slope of the line with the given points from the table, <math alttext=\"left parenthesis k comma 13 right parenthesis\"><mo>(</mo><mi>k</mi><mo>,</mo><mn>13</mn><mo>)</mo></math>&nbsp;and&nbsp;<math alttext=\"left parenthesis k plus 7 comma negative 15 right parenthesis\"><mo>(</mo><mi>k</mi><mo>+</mo><mn>7</mn><mo>,</mo><mo>-</mo><mn>15</mn><mo>)</mo></math>, is&nbsp;<math alttext=\"m equals StartFraction negative 15 minus 13 Over k plus 7 minus k EndFraction\"><mi>m</mi><mo>=</mo><mfrac><mrow><mo>-</mo><mn>15</mn><mo>-</mo><mn>13</mn></mrow><mrow><mi>k</mi><mo>+</mo><mn>7</mn><mo>-</mo><mi>k</mi></mrow></mfrac></math>, which is equivalent to&nbsp;<math alttext=\"m equals StartFraction negative 28 Over 7 EndFraction\"><mi>m</mi><mo>=</mo><mfrac><mrow><mo>-</mo><mn>28</mn></mrow><mn>7</mn></mfrac></math>, or&nbsp;<math alttext=\"m equals negative 4\"><mi>m</mi><mo>=</mo><mo>-</mo><mn>4</mn></math>. It's given that the&nbsp;<em>y</em>-intercept of the line is&nbsp;<math alttext=\"left parenthesis k minus 5 comma b right parenthesis\"><mo>(</mo><mi>k</mi><mo>-</mo><mn>5</mn><mo>,</mo><mi>b</mi><mo>)</mo></math>. Substituting <math alttext=\"negative 4\"><mo>-</mo><mn>4</mn>\n</math> for <math alttext=\"m\"><mi>m</mi>\n</math> and the coordinates of the points <math alttext=\"left parenthesis k minus 5 comma b right parenthesis\"><mo>(</mo><mi>k</mi><mo>-</mo><mn>5</mn><mo>,</mo><mi>b</mi><mo>)</mo></math> and&nbsp;<math alttext=\"left parenthesis k comma 13 right parenthesis\"><mo>(</mo><mi>k</mi><mo>,</mo><mn>13</mn><mo>)</mo></math> into the slope formula yields <math alttext=\"negative 4 equals StartFraction 13 minus b Over k minus left parenthesis k minus 5 right parenthesis EndFraction\"><mo>-</mo><mn>4</mn><mo>=</mo><mfrac><mrow><mn>13</mn><mo>-</mo><mi>b</mi></mrow><mrow><mi>k</mi><mo>-</mo><mfenced><mrow><mi>k</mi><mo>-</mo><mn>5</mn></mrow></mfenced></mrow></mfrac></math>, which is equivalent to&nbsp;<math alttext=\"negative 4 equals StartFraction 13 minus b Over k minus k plus 5 EndFraction\"><mo>-</mo><mn>4</mn><mo>=</mo><mfrac><mrow><mn>13</mn><mo>-</mo><mi>b</mi></mrow><mrow><mi>k</mi><mo>-</mo><mi>k</mi><mo>+</mo><mn>5</mn></mrow></mfrac></math>, or <math alttext=\"negative 4 equals StartFraction 13 minus b Over 5 EndFraction\"><mo>-</mo><mn>4</mn><mo>=</mo><mfrac><mrow><mn>13</mn><mo>-</mo><mi>b</mi></mrow><mn>5</mn></mfrac></math>. Multiplying both sides of this equation by <math alttext=\"5\"><mn>5</mn>\n</math> yields <math alttext=\"negative 20 equals 13 minus b\"><mo>-</mo><mn>20</mn><mo>=</mo><mn>13</mn><mo>-</mo><mi>b</mi></math>. Subtracting <math alttext=\"13\"><mn>13</mn>\n</math> from both sides of this equation yields&nbsp;<math alttext=\"negative 33 equals negative b\"><mo>-</mo><mn>33</mn><mo>=</mo><mo>-</mo><mi>b</mi></math>. Dividing both sides of this equation by&nbsp;<math alttext=\"negative 1\"><mo>-</mo><mn>1</mn></math> yields <math alttext=\"b equals 33\"><mi>b</mi><mo>=</mo><mn>33</mn></math>. Therefore, the value of <math alttext=\"b\"><mi>b</mi>\n</math> is <math alttext=\"33\"><mn>33</mn>\n</math>.</p>","correct_answer":["33"],"has_media":false,"has_mathml":true,"has_table":true,"source_created_at":"2023-08-02T20:25:59.815000+00:00","source_updated_at":"2023-08-02T20:25:59.815000+00:00","options":[],"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}}