4 : n = 12 :15
You asked:
Solve \(4 : n=12 : 15\) for the variable \(n\).
MathBot Answer:
$$\begin{aligned}n &= 5\end{aligned}$$
Express both ratios as fractions. \[\frac{4}{n} = \frac{12}{15}\]
Cross-multiply and solve for the unknown. $$\begin{aligned}\frac{4}{n} &= \frac{12}{15} \\ 60 &= 12 n \\ n &&= 5 \end{aligned}$$