{"common":{"save":0,"post_id":"7780","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"7217","post_id":"7780","mon_id":"1159278","chapter_id":"1159282","question":"<p>Hai v&ograve;i n\u01b0\u1edbc c&ugrave;ng&nbsp;ch\u1ea3y v&agrave;o b\u1ec3 th&igrave; sau 24 gi\u1edd \u0111\u1ea7y b\u1ec3. N\u1ebfu&nbsp;v&ograve;i th\u1ee9 nh\u1ea5t ch\u1ea3y 3&nbsp;gi\u1edd, v&ograve;i th\u1ee9 hai ch\u1ea3y 6 gi\u1edd th&igrave; \u0111\u01b0\u1ee3c&nbsp;<span class=\"math-tex\">$\\dfrac{1}{3}$<\/span> b\u1ec3. N\u1ebfu g\u1ecdi&nbsp;x&nbsp;gi\u1edd l&agrave; th\u1eddi gian v&ograve;i th\u1ee9 nh\u1ea5t ch\u1ea3y m\u1ed9t&nbsp;m&igrave;nh \u0111\u1ea7y b\u1ec3 th&igrave; s\u1ed1 ph\u1ea7n n\u01b0\u1edbc trong b\u1ec3 v&ograve;i th\u1ee9 hai ch\u1ea3y&nbsp;m\u1ed9t m&igrave;nh trong 6 gi\u1edd l&agrave;<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$\\dfrac{6}{x}+24.\\bigg(\\dfrac{1}{3}-\\dfrac{1}{x}\\bigg)$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$6.\\bigg(\\dfrac{1}{24}-\\dfrac{1}{x}\\bigg)$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$24.\\bigg(\\dfrac{1}{6}-\\dfrac{1}{x}\\bigg)$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$\\dfrac{6}{x}+3.\\bigg(\\dfrac{1}{24}-\\dfrac{1}{x}\\bigg)$<\/span>"],"correct":"2","level":"2","hint":"","answer":"<p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><strong>B.<\/strong>&nbsp;<span class=\"math-tex\">$6.\\bigg(\\dfrac{1}{24}-\\dfrac{1}{x}\\bigg)$<\/span><\/span><\/p><p>Th\u1eddi gian v&ograve;i th\u1ee9 nh\u1ea5t ch\u1ea3y m\u1ed9t m&igrave;nh \u0111\u1ea7y b\u1ec3 l&agrave; x gi\u1edd<\/p><p>M\u1ed7i gi\u1edd v&ograve;i th\u1ee9 nh\u1ea5t ch\u1ea3y \u0111\u01b0\u1ee3c&nbsp;<span class=\"math-tex\">$\\dfrac{1}{x}$<\/span>&nbsp;b\u1ec3.<\/p><p>M\u1ed7i gi\u1edd c\u1ea3 hai v&ograve;i ch\u1ea3y \u0111\u01b0\u1ee3c&nbsp;<span class=\"math-tex\">$\\dfrac{1}{24}$<\/span>&nbsp;b\u1ec3<\/p><p>M\u1ed7i gi\u1edd v&ograve;i th\u1ee9 hai ch\u1ea3y \u0111\u01b0\u1ee3c&nbsp;<span class=\"math-tex\">$\\dfrac{1}{24}-\\dfrac{1}{x}$<\/span>&nbsp;b\u1ec3<\/p><p>S\u1ed1 ph\u1ea7n n\u01b0\u1edbc trong b\u1ec3 v&ograve;i th\u1ee9 hai ch\u1ea3y m\u1ed9t m&igrave;nh trong 6&nbsp;gi\u1edd l&agrave;&nbsp;<span style=\"color:#16a085;\"><span class=\"math-tex\">$6.\\bigg(\\dfrac{1}{24}-\\dfrac{1}{x}\\bigg)$<\/span><\/span>.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-04 02:14:07","option_type":"math","len":0},{"id":"7218","post_id":"7780","mon_id":"1159278","chapter_id":"1159282","question":"<p>Hi\u1ec7n nay, m\u1eb9 Lan h\u01a1n Lan 20&nbsp;tu\u1ed5i. Sau 5 n\u0103m n\u1eefa, n\u1ebfu&nbsp;s\u1ed1 tu\u1ed5i c\u1ee7a Lan l&agrave; x (tu\u1ed5i) th&igrave; s\u1ed1 tu\u1ed5i c\u1ee7a m\u1eb9 Lan hi\u1ec7n nay&nbsp;l&agrave;<\/p>","options":["<strong>A.<\/strong> x &ndash; 15","<strong>B.<\/strong> x + 25","<strong>C.<\/strong> x + 20","<strong>D.<\/strong> x + 15"],"correct":"4","level":"2","hint":"","answer":"<p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><strong>D.<\/strong>&nbsp;x + 15<\/span><\/p><p>S\u1ed1 tu\u1ed5i c\u1ee7a Lan sau 5 n\u0103m l&agrave; x&nbsp;(tu\u1ed5i).<\/p><p>S\u1ed1 tu\u1ed5i c\u1ee7a Lan hi\u1ec7n nay l&agrave; x&nbsp;&ndash; 5&nbsp;(tu\u1ed5i).<\/p><p>S\u1ed1 tu\u1ed5i c\u1ee7a m\u1eb9 Lan hi\u1ec7n nay l&agrave; x&nbsp;&ndash; 5 + 20 = <span style=\"color:#16a085;\"><strong>x + 15&nbsp;(tu\u1ed5i)<\/strong><\/span>.<\/p>","type":"choose","extra_type":"shape1","time":"0","user_id":"127","test":"0","date":"2024-10-04 02:16:34","option_type":"txt","len":0},{"id":"7220","post_id":"7780","mon_id":"1159278","chapter_id":"1159282","question":"<p>Nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr&igrave;nh <span class=\"math-tex\">$x^2-4x+4=0$<\/span>&nbsp;l&agrave;<\/p>","options":["<strong>A.<\/strong> x = 2","<strong>B.<\/strong> x = &ndash;2","<strong>C.<\/strong> x = 4","<strong>D.<\/strong> x = &ndash;4"],"correct":"1","level":"2","hint":"","answer":"<p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><strong>A.<\/strong>&nbsp;x = 2<\/span><\/p><p><span class=\"math-tex\">$x^2-4x+4=0$<\/span>&nbsp;hay&nbsp;<span class=\"math-tex\">$(x-2)^2=0$<\/span>&nbsp;suy ra x = 2.<\/p><p>V\u1eady nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr&igrave;nh&nbsp;<span class=\"math-tex\">$x^2-4x+4=0$<\/span> l&agrave; x = 2.<\/p>","type":"choose","extra_type":"shape2","time":"0","user_id":"127","test":"0","date":"2024-10-04 02:18:39","option_type":"txt","len":0}]}