[tex] \frac{k}{13} [/tex] = [tex] \frac{0.6}{0.5} [/tex] equals k = 15.6
First, simplify [tex] \frac{0.6}{0.5} [/tex] to 1.2. Your problem should look like: [tex] \frac{k}{13} [/tex] = 1.2
Second, multiply both sides by 13. Your problem should look like: k = 15.6, which is the answer.
