第47页

信息发布者:
解:$\frac{4}{5}x - \frac{3}{4}x = \frac{3}{4}$
$\frac{16}{20}x - \frac{15}{20}x = \frac{3}{4}$
$\frac{1}{20}x = \frac{3}{4}$
$x = \frac{3}{4} \div \frac{1}{20}$
$x = \frac{3}{4} \times 20$
$x = 15$
解:$\frac{5}{6}x - 0.25 = \frac{3}{4}$
$\frac{5}{6}x = \frac{3}{4} + 0.25$
$\frac{5}{6}x = \frac{3}{4} + \frac{1}{4}$
$\frac{5}{6}x = 1$
$x = 1 \div \frac{5}{6}$
$x = 1 \times \frac{6}{5}$
$x = \frac{6}{5}$
$\frac{16}{11} - (\frac{5}{11} - \frac{2}{9})$
$=\frac{16}{11} - \frac{5}{11} + \frac{2}{9}$
$=1 + \frac{2}{9}$
$=1\frac{2}{9}$
$(\frac{5}{24} + \frac{7}{12} - \frac{2}{3})×48$
$=\frac{5}{24}×48 + \frac{7}{12}×48 - \frac{2}{3}×48$
$=10 + 28 - 32$
$=6$
$30×(\frac{1}{15} + \frac{2}{17})×17$
$=30×\frac{1}{15}×17 + 30×\frac{2}{17}×17$
$=34 + 60$
$=94$
$\frac{4}{5}×\frac{4}{7}×\frac{5}{4} - \frac{1}{2}$
$=\frac{4}{5}×\frac{5}{4}×\frac{4}{7} - \frac{1}{2}$
$=1×\frac{4}{7} - \frac{1}{2}$
$=\frac{4}{7} - \frac{1}{2}$
$=\frac{8}{14} - \frac{7}{14}$
$=\frac{1}{14}$
$\frac{4}{5}×\frac{5}{6} + \frac{2}{5}÷\frac{6}{5}$
$=\frac{2}{3} + \frac{2}{5}×\frac{5}{6}$
$=\frac{2}{3} + \frac{1}{3}$
$=1$
$\frac{4}{5}÷[(\frac{5}{8} - \frac{1}{2})÷\frac{5}{8}]$
$=\frac{4}{5}÷[(\frac{5}{8} - \frac{4}{8})÷\frac{5}{8}]$
$=\frac{4}{5}÷[\frac{1}{8}÷\frac{5}{8}]$
$=\frac{4}{5}÷\frac{1}{5}$
$=\frac{4}{5}×5$
$=4$
B
C
$\frac{27}{140}$
​$(\frac {1}{4}+\frac {1}{5})×3=\frac {27}{20}($​千克​$)$​
答:一共​$\frac {27}{20}$​千克。
​$64×\frac {1}{4}×28=448($​元​$)$​
​$448÷(32×\frac {1}{5})=70($​包​$)$​
答:需要​$448$​元,可以买​$70$​包​$B$​品牌香瓜子。
$\frac{1}{6}$
$\frac{8}{7}$