$(x+2)/20=1/5$. What is $x$? $(x+2)/20=1/5$. I have been stuck on this problem and tried various solutions to no avail. Please help.
$$
\frac{x+2}{20}=\frac{1}{5} \tag*{ – multiply both sides by $20$}
$$
$$
\frac{x+2}{1}=\frac{20}{5} \tag*{  – simplify}
$$
$$
x+2=4 \tag*{  – substract $2$ from both sides}
$$
$$
x=2 \tag*{  – the answer}
$$
In general, whenever dealing with a fraction equality such as$$\frac{a}{b} = \frac{c}{d},$$ remember the extremes rule: $$a \times d = b \times c.$$

Applied to your case, this gives $$5 \times (x+2) = 20\times 1$$ which we now expand to $$5x + 10 = 20$$ leading to $$5x = 10$$ and thus $$x=2.$$