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#1
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⨷Âì»ÑËÒàÈÉÊèǹ¾ËعÒÁ
á´§áÅдÓà´Ô¹·Ò§ÍÍ¡¨Ò¡ºéÒ¹«Öè§ÍÂÙèËèÒ§¡Ñ¹ 15 ¡ÔâÅàÁµÃ á´§ÍÍ¡à´Ô¹·Ò§ËÅѧ¨Ò¡´ÓÍÍ¡à´Ô¹·Ò§
ä´é 1 ªÑèÇâÁ§ 20 ¹Ò·Õ à¢Ò¾º¡Ñ¹àÁ×èÍá´§à´Ô¹ä´é 2 ªÑèÇâÁ§¾Í´Õ ¶éÒá´§ÍÍ¡à´Ô¹·Ò§¡è͹´Ó¤ÃÖ觪ÑèÇâÁ§ ¨Ð¾º¡Ñ¹µÃ§¡Ö觡ÅÒ§¾Í´Õ ¨§ËÒÇèÒá´§à´Ô¹·Ò§´éÇÂÍѵÃÒàÃçǪÑèÇâÁ§ÅСÕè¡Ô´ÅàÁµÃ áÊ´§ÇÔ·Õ·Ó´éǹФÃѺ ¢Íº¤Ø³ÁÒ¡¤Ñº |
#2
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¤ÓµÍºÍÍ¡ÁÒäÁèŧµÑÇ
¤×Í»ÃÐÁÒ³2.778¹Ð¤ÃѺ |
#3
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àÁ×èÍá´§ÍÍ¡¡è͹´Ó¤ÃÖ觪ÑèÇâÁ§ à¨Í¡Ñ¹¤ÃÖ觷ҧ
ãËéá´§à´Ô¹ä´éàÃçÇ R ¡Á/ªÁ ãËé´Óà´Ô¹ä´éàÃçÇ B ¡Á/ªÁ $\frac{7.5}{R} = \frac{7.5}{B} + 0.5$ $\frac{7.5}{R} = \frac{7.5 + 0.5 B}{B}$ $7.5 B = R (7.5 + 0.5 B)$ $\frac{7.5 B}{7.5 + 0.5 B} = R$ àÁ×èÍá´§ÍÍ¡ËÅѧ´Ó 1 ªÑèÇâÁ§ 20 ¹Ò·Õ à¨Í¡Ñ¹ËÅѧ¨Ò¡á´§à´Ô¹ä´é 2 ªÁ ´Ñ§¹Ñé¹´Óà´Ô¹ä´é $3\frac{1}{3} = \frac{10}{3}$ ªÁ $2 R + \frac{10}{3} B = 15$ $2(\frac{7.5 B}{7.5 + 0.5 B}) + \frac{10}{3} B = 15$ $\frac{45 B + 75 B + 5 B^2}{22.5 + 1.5 B}= 15$ $5B^2 + 120 B = 337.5 + 22.5 B$ $5B^2 + 97.5 B - 337.5 = 0$ $B^2 + 19.5 B - 67.5 = 0$ (B - 3) (B + 22.5) = 0 B = 3 ¡Á/ªÁ R = 2.5 ¡Á/ªÁ |
#4
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àÍèÍ Ê§ÊѹԴ¹Ö§ÇèÒ
⨷ÂìẺ¹Õé ¨¢¡·.àÃÕ¡ÇèÒàÈÉÊèǹ¾ËعÒÁËÃ×Í?? |
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