第35页

信息发布者:
解:
$\begin{aligned}&\frac{7}{3}-\frac{5}{6}\times\frac{3}{10}+\frac{3}{4}\\=&\frac{7}{3}-\frac{1}{4}+\frac{3}{4}\\=&\frac{7}{3}+(\frac{3}{4}-\frac{1}{4})\\=&\frac{7}{3}+\frac{1}{2}\\=&\frac{14}{6}+\frac{3}{6}\\=&\frac{17}{6}\end{aligned}$
解:
$\begin{aligned}&\frac{3}{5}\times15+\frac{2}{5}\div\frac{1}{15}\\=&\frac{3}{5}\times15+\frac{2}{5}\times15\\=&(\frac{3}{5}+\frac{2}{5})\times15\\=&1\times15\\=&15\end{aligned}$
解:
$\begin{aligned}&(\frac{1}{5}+\frac{1}{3})\div\frac{1}{45}\div\frac{12}{5}\\=&(\frac{1}{5}+\frac{1}{3})\times45\times\frac{5}{12}\\=&\frac{1}{5}\times45\times\frac{5}{12}+\frac{1}{3}\times45\times\frac{5}{12}\\=&\frac{15}{4}+\frac{25}{4}\\=&10\end{aligned}$
解:
$\begin{aligned}\frac{3}{7}x\div2&=\frac{9}{10}\\\frac{3}{7}x&=\frac{9}{5}\\x&=\frac{21}{5}\end{aligned}$
解:
$\begin{aligned}\frac{5}{8}+\frac{3}{8}x&=\frac{5}{2}\\\frac{3}{8}x&=\frac{15}{8}\\x&=5\end{aligned}$
解:
$\begin{aligned}90\%x - 75\%x&=150\\15\%x&=150\\x&=1000\end{aligned}$


解:全班人数:$15 + 35 = 50$(人)
不会弹琵琶的人数:$50 - 30 = 20$(人)
不会弹琵琶的学生占全班人数:$20\div50\times100\% = 40\%$
答:不会弹琵琶的占全班人数的40%。