Practice Solutions

1. $\frac{10}{21}=\frac{x}{7}$

$\begin{array}{rcl}10\left(7\right)& =& 21x\\ \frac{70}{21}& =& \frac{21x}{21}\\ x& =& \frac{70}{21}=\frac{10}{3}\end{array}$

2. $\frac{5}{12}=\frac{x}{18}$

$\begin{array}{rcl}5\left(18\right)& =& 12x\\ \frac{90}{12}& =& \frac{12x}{12}\\ x& =& \frac{90}{12}=\frac{15}{2}\end{array}$

3. $\frac{x}{8}=\frac{11}{5}$

$\begin{array}{rcl}5x& =& 8\left(11\right)\\ \frac{5x}{5}& =& \frac{88}{5}\\ x& =& \frac{88}{5}\end{array}$

4. $\frac{7x}{5}=\frac{13}{11}$

$\begin{array}{rcl}7x\left(11\right)& =& 5\left(13\right)\\ \frac{77x}{77}& =& \frac{65}{77}\\ x& =& \frac{65}{77}\end{array}$

5. $\frac{3x}{15}=\frac{52}{5}$

$\begin{array}{rcl}3x\left(5\right)& =& 52\left(15\right)\\ \frac{15x}{15}& =& \frac{52\left(15\right)}{15}\\ x& =& 52\end{array}$

6. $\frac{9}{35}=\frac{x}{75}$

$\begin{array}{rcl}9\left(75\right)& =& 35x\\ \frac{675}{35}& =& \frac{35x}{35}\\ x& =& \frac{675}{35}=\frac{135}{7}\end{array}$

7. $\frac{x}{100}=\frac{3}{8}$

$\begin{array}{rcl}8x& =& 100\left(3\right)\\ \frac{8x}{8}& =& \frac{300}{8}\\ x& =& \frac{300}{8}=\frac{75}{2}\end{array}$

8. $\frac{2x}{15}=\frac{3}{4}$

$\begin{array}{rcl}2x\left(4\right)& =& 3\left(15\right)\\ \frac{8x}{8}& =& \frac{45}{8}\\ x& =& \frac{45}{8}\end{array}$

9. $\frac{7}{15}=\frac{2}{x}$

$\begin{array}{rcl}7x& =& 15\left(2\right)\\ \frac{7x}{7}& =& \frac{30}{7}\\ x& =& \frac{30}{7}\end{array}$

10. $\frac{20}{x}=\frac{5}{3}$

$\begin{array}{rcl}20\left(3\right)& =& 5x\\ \frac{60}{5}& =& \frac{5x}{5}\\ x& =& 12\end{array}$

11. $\frac{26}{5}=\frac{x}{15}$

$\begin{array}{rcl}26\left(15\right)& =& 5x\\ \frac{390}{5}& =& \frac{5x}{5}\\ x& =& 78\end{array}$

12. $\frac{13}{3x}=\frac{1}{5}$

$\begin{array}{rcl}13\left(5\right)& =& 3x\\ \frac{65}{3}& =& \frac{3x}{3}\\ x& =& \frac{65}{3}\end{array}$