{"common":{"save":0,"post_id":"4765","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"7858","post_id":"4765","mon_id":"1158113","chapter_id":"1158119","question":"<p>Có bao nhiêu phân s\u1ed1 b\u1eb1ng phân s\u1ed1 <span class=\"math-tex\">$\\dfrac{15}{36}$<\/span> mà t\u1eed và m\u1eabu s\u1ed1 là các s\u1ed1 t\u1ef1 nhiên có hai ch\u1eef s\u1ed1?<\/p>","options":["8","7","5","6"],"correct":"4","level":"3","hint":"<p>B\u01b0\u1edbc 1: Rút g\u1ecdn phân s\u1ed1 \u0111ã cho v\u1ec1 t\u1ed1i gi\u1ea3n.<\/p><p>B\u01b0\u1edbc 2: L\u1ea7n l\u01b0\u1ee3t nhân c\u1ea3 t\u1eed và m\u1eabu c\u1ee7a phân s\u1ed1 t\u1ed1i gi\u1ea3n v\u1eeba tìm \u0111\u01b0\u1ee3c v\u1edbi 2 ; 3 ; 4 ; 5 ; ... sao cho t\u1eed và m\u1eabu c\u1ee7a phân s\u1ed1 nh\u1eadn \u0111\u01b0\u1ee3c v\u1eabn là các s\u1ed1 t\u1ef1 nhiên có hai ch\u1eef s\u1ed1.<\/p><p>B\u01b0\u1edbc 3: \u0110\u1ebfm s\u1ed1 các phân s\u1ed1 th\u1ecfa mãn yêu c\u1ea7u bài toán.<\/p>","answer":"<p>Ta có <span class=\"math-tex\">$\\dfrac{15}{36}=\\dfrac{15:3}{36:3}=\\dfrac{5}{12}$<\/span><\/p><p> <span class=\"math-tex\">$\\dfrac{5}{12}=\\dfrac{5.2}{12.2}=\\dfrac{10}{24}$<\/span><\/p><p> <span class=\"math-tex\">$\\dfrac{5}{12}=\\dfrac{5.3}{12.3}=\\dfrac{15}{36}$<\/span><\/p><p> <span class=\"math-tex\">$\\dfrac{5}{12}=\\dfrac{5.4}{12.4}=\\dfrac{20}{48}$<\/span><\/p><p> <span class=\"math-tex\">$\\dfrac{5}{12}=\\dfrac{5.5}{12.5}=\\dfrac{25}{60}$<\/span><\/p><p> <span class=\"math-tex\">$\\dfrac{5}{12}=\\dfrac{5.6}{12.6}=\\dfrac{30}{72}$<\/span><\/p><p> <span class=\"math-tex\">$\\dfrac{5}{12}=\\dfrac{5.7}{12.7}=\\dfrac{35}{84}$<\/span><\/p><p> <span class=\"math-tex\">$\\dfrac{5}{12}=\\dfrac{5.8}{12.8}=\\dfrac{40}{96}$<\/span><\/p><p>Nh\u01b0 v\u1eady có <span style=\"color:#16a085;\">6 phân s\u1ed1 <\/span>b\u1eb1ng phân s\u1ed1<strong> <span class=\"math-tex\">$\\dfrac{15}{36}$<\/span> <\/strong>là<strong> <span style=\"color:#16a085;\"> <span class=\"math-tex\">$\\dfrac{10}{24} ; \\dfrac{20}{48} ; \\dfrac{25}{60};\\dfrac{30}{72};\\dfrac{35}{84};\\dfrac{40}{96}$<\/span><\/span><\/strong><\/p><p>\u0110áp án \u0111úng là <span style=\"color:#16a085;\"><strong>6 <\/strong><\/span>(ngôi sao ch\u1ee9a s\u1ed1 6)<\/p>","type":"choose","extra_type":"star","time":"0","user_id":"131","test":"3","date":"2021-09-30 12:10:01","option_type":"txt","len":0},{"id":"7861","post_id":"4765","mon_id":"1158113","chapter_id":"1158119","question":"<p>M\u1ed9t ng\u01b0\u1eddi c\u1ea7n 90 phút \u0111\u1ec3 hoàn thành m\u1ed9t công vi\u1ec7c. H\u1ecfi sau 36 phút ng\u01b0\u1eddi \u0111ó làm \u0111\u01b0\u1ee3c bao nhiêu ph\u1ea7n công vi\u1ec7c?<\/p>","options":["<span class=\"math-tex\">$\\dfrac{1}{5}$<\/span>","<span class=\"math-tex\">$\\dfrac{2}{5}$<\/span> công vi\u1ec7c","<span class=\"math-tex\">$\\dfrac{36}{90}$<\/span>"],"correct":"2","level":"3","hint":"<p>S\u1ed1 ph\u1ea7n công vi\u1ec7c = <span class=\"frac123\"><span class=\"ts\">Th\u1eddi gian làm vi\u1ec7c<\/span><span class=\"ms\">Th\u1eddi gian c\u1ea7n \u0111\u1ec3 hoàn thành công vi\u1ec7c<\/span><\/span><\/p>","answer":"<p>Thòi gian ng\u01b0\u1eddi \u0111ó làm vi\u1ec7c là 36 phút.<\/p><p>Th\u1eddi gian c\u1ea7n \u0111\u1ec3 ng\u01b0\u1eddi \u0111ó hoàn thành công vi\u1ec7c là 90 phút.<\/p><p>S\u1ed1 ph\u1ea7n công vi\u1ec7c mà ng\u01b0\u1eddi \u0111ó \u0111ã làm \u0111\u01b0\u1ee3c sau 36 phút là:<\/p><p><span class=\"math-tex\">$\\dfrac{36}{90}=\\dfrac{36:18}{90:18}=\\dfrac{2}{5}$<\/span> (công vi\u1ec7c)<\/p><p>\u0110áp án \u0111úng là <span style=\"color:#16a085;\"><span class=\"math-tex\">$\\dfrac{2}{5}$<\/span> công vi\u1ec7c<\/span><\/p><p><span style=\"color:#2980b9;\">Chú ý: H\u1ecdc sinh c\u1ea7n rút g\u1ecdn v\u1ec1 phân s\u1ed1 t\u1ed1i gi\u1ea3n.<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"3","date":"2021-09-30 12:19:47","option_type":"math","len":0},{"id":"7863","post_id":"4765","mon_id":"1158113","chapter_id":"1158119","question":"<p>Rút g\u1ecdn phân s\u1ed1 sau v\u1ec1 t\u1ed1i gi\u1ea3n<\/p><p><span class=\"math-tex\">$\\dfrac{13^2.2^5}{13^3.2^3}$<\/span><\/p>","options":["<span class=\"math-tex\">$\\dfrac{4}{13}$<\/span>","<span class=\"math-tex\">$\\dfrac{13}{4}$<\/span>","<span class=\"math-tex\">$\\dfrac{2}{13}$<\/span>","<span class=\"math-tex\">$\\dfrac{13}{2}$<\/span>"],"correct":"1","level":"3","hint":"<p>Chú ý rút g\u1ecdn các l\u0169y th\u1eeba có cùng c\u01a1 s\u1ed1 \u1edf t\u1eed và m\u1eabu.<\/p><p>Công th\u1ee9c <span class=\"math-tex\">$a^m:a^n=a^{m-n}$<\/span> <\/p>","answer":"<p>Ta có: <span class=\"math-tex\">$\\dfrac{13^2.2^5}{13^3.2^3}=\\dfrac{2^2}{13}=\\dfrac{4}{13}$<\/span> (rút g\u1ecdn cho <span class=\"math-tex\">$13^2 . 2^3$<\/span>)<\/p><p>\u0110áp án \u0111úng là <span style=\"color:#16a085;\"><span class=\"math-tex\">$\\dfrac{4}{13}$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"1","date":"2021-09-30 12:26:31","option_type":"math","len":0}]}