{"common":{"save":0,"post_id":"946","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"601","post_id":"946","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":" <span class='basic_left'>Cho bi\u1ebft t t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi z theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 l\u00e0 a, z t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi y theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 l\u00e0 b, y t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi x theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 l\u00e0 c ( a, b, c l\u00e0 c\u00e1c h\u1eb1ng s\u1ed1 kh\u00e1c 0). t t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi x theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 l\u00e0? <\/span>","select":["A. a + b + c ","B. abc","C. a - b - c ","D. a : b : c "],"explain":"<span class='basic_left'> Ta c\u00f3: t t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi z theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 l\u00e0 a n\u00ean t = az (1)<br\/> z t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi y theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 l\u00e0 b n\u00ean z = by (2) <br\/> y t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi x theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 l\u00e0 c n\u00ean y = cx (3) <br\/> T\u1eeb (1), (2) v\u00e0 (3) ta c\u00f3: t = a.(by) = ab.(cx) = abc.x <br\/> Suy ra t t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi x theo h\u1ec7 s\u1ed1 t\u1ec9 l\u1ec7 l\u00e0 abc. <br\/><span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span><\/span> ","column":2}]}]},"correct":"","level":"3","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:49"},{"id":"602","post_id":"946","mon_id":"0","chapter_id":"0","question":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng ","options":{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["75"]]],"list":[{"point":10,"width":50,"type_input":"","ques":" <span class='basic_left'>V\u1edbi s\u1ed1 ti\u1ec1n \u0111\u1ec3 mua 60 m v\u1ea3i lo\u1ea1i I c\u00f3 th\u1ec3 mua \u0111\u01b0\u1ee3c bao nhi\u00eau m\u00e9t v\u1ea3i lo\u1ea1i II? Bi\u1ebft r\u1eb1ng gi\u00e1 ti\u1ec1n v\u1ea3i lo\u1ea1i II b\u1eb1ng 80% gi\u00e1 ti\u1ec1n v\u1ea3i lo\u1ea1i I. <br\/> \u0110\u00e1p s\u1ed1: $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{} (m)$ <\/span> ","explain":"<span class='basic_left'> G\u1ecdi $x$ (m) l\u00e0 s\u1ed1 m\u00e9t v\u1ea3i lo\u1ea1i II mua \u0111\u01b0\u1ee3c v\u1edbi s\u1ed1 ti\u1ec1n \u0111\u1ec3 mua 60m v\u1ea3i lo\u1ea1i I, ta c\u00f3: <br\/> $ \\dfrac{x}{60} = \\dfrac{\\text{gi\u00e1 1m v\u1ea3i lo\u1ea1i I}}{\\text{gi\u00e1 1m v\u1ea3i lo\u1ea1i II}} = \\dfrac{100}{80} = \\dfrac{5}{4} $ <br\/> Suy ra $ x = \\dfrac{60.5}{4} = 75 $ <br\/> V\u1eady v\u1edbi c\u00f9ng s\u1ed1 ti\u1ec1n mua 60m v\u1ea3i lo\u1ea1i I th\u00ec mua \u0111\u01b0\u1ee3c 75m v\u1ea3i lo\u1ea1i II. <br\/><span class='basic_pink'> V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u00e0 75. <\/span><\/span> "}]}]},"correct":"","level":"3","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:49"},{"id":"603","post_id":"946","mon_id":"0","chapter_id":"0","question":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng ","options":{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["450"]]],"list":[{"point":10,"width":50,"type_input":"","ques":" <span class='basic_left'> Hai \u00f4 t\u00f4 kh\u1edfi h\u00e0nh c\u00f9ng m\u1ed9t l\u00fac t\u1eeb hai \u0111\u1ecba \u0111i\u1ec3m A v\u00e0 B, \u0111i ng\u01b0\u1ee3c chi\u1ec1u nhau. Khi g\u1eb7p nhau \u00f4 t\u00f4 t\u1eeb B \u0111i \u0111\u01b0\u1ee3c qu\u00e3ng \u0111\u01b0\u1eddng d\u00e0i h\u01a1n qu\u00e3ng \u0111\u01b0\u1eddng \u00f4 t\u00f4 \u0111i t\u1eeb A l\u00e0 50 km. T\u00ednh qu\u00e3ng \u0111\u01b0\u1eddng AB, bi\u1ebft v\u1eadn t\u1ed1c c\u1ee7a \u00f4 t\u00f4 \u0111i t\u1eeb A v\u00e0 B t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi 4 v\u00e0 5? <br\/> \u0110\u00e1p s\u1ed1: $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{} (km)$ <\/span> ","hint":"L\u1ea5y t\u1ec9 l\u1ec7 v\u1ec1 qu\u00e3ng \u0111\u01b0\u1eddng v\u00e0 v\u1eadn t\u1ed1c. ","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u01b0\u1edbc 1: X\u00e1c \u0111\u1ecbnh quan h\u1ec7 t\u1ec9 l\u1ec7 thu\u1eadn gi\u1eefa hai \u0111\u1ea1i l\u01b0\u1ee3ng $y$ v\u00e0 $x$. <br\/>B\u01b0\u1edbc 2: \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t t\u1ec9 s\u1ed1 hai gi\u00e1 tr\u1ecb b\u1ea5t k\u00ec c\u1ee7a \u0111\u1ea1i l\u01b0\u1ee3ng n\u00e0y b\u1eb1ng t\u1ec9 s\u1ed1 hai gi\u00e1 tr\u1ecb t\u01b0\u01a1ng \u1ee9ng c\u1ee7a \u0111\u1ea1i l\u01b0\u1ee3ng kia. <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span> <br\/> G\u1ecdi qu\u00e3ng \u0111\u01b0\u1eddng \u00f4 t\u00f4 xu\u1ea5t ph\u00e1t t\u1eeb A \u0111\u1ebfn ch\u1ed7 g\u1eb7p nhau l\u00e0 $S_{1}$, v\u1edbi v\u1eadn t\u1ed1c l\u00e0 $v_{1}$. <br\/> Qu\u00e3ng \u0111\u01b0\u1eddng \u00f4 t\u00f4 xu\u1ea5t ph\u00e1t t\u1eeb B \u0111\u1ec5n ch\u1ed7 g\u1eb7p nhau l\u00e0 $S_{2}$, v\u1edbi v\u1eadn t\u1ed1c l\u00e0 $v_{2}$. <br\/> Theo \u0111\u1ec1 b\u00e0i ta c\u00f3: $S_{2} - S_{1} = 50$ v\u00e0 $ \\dfrac{v_{1}}{4} = \\dfrac{v_{2}}{5} \\Rightarrow \\dfrac{v_{1}}{v_{2}} = \\dfrac{4}{5} $ <br\/> V\u1edbi c\u00f9ng m\u1ed9t th\u1eddi gian th\u00ec qu\u00e3ng \u0111\u01b0\u1eddng v\u00e0 v\u1eadn t\u1ed1c l\u00e0 hai \u0111\u1ea1i l\u01b0\u1ee3ng t\u1ec9 l\u1ec7 thu\u1eadn, n\u00ean ta c\u00f3: <br\/> $ \\dfrac{S_{1}}{S_{2}} = \\dfrac{v_{1}}{v_{2}} = \\dfrac{4}{5} $ <br\/> Do \u0111\u00f3 $\\dfrac{S_{1}}{4} = \\dfrac{S_{2}}{5} = \\dfrac{S_{2}-S_{1}}{5-4} = \\dfrac{50}{1} = 50 $ <br\/> V\u1eady $S_{1} = 50.4 = 200 \\\\ S_{2} = 50.5 = 250$ <br\/> Qu\u00e3ng \u0111\u01b0\u1eddng AB d\u00e0i l\u00e0 : 200 + 250 = 450 (km).<br\/><span class='basic_pink'> V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u00e0 450. <\/span><\/span> "}]}]},"correct":"","level":"3","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:22:49"}]}