Calculation:

The given ratios can be simplified further by doing cross product:

\(\displaystyle{\frac{{{10}}}{{{15}}}}={\frac{{{4}}}{{{x}-{5}}}}\)

\(\displaystyle{10}{\left({x}-{5}\right)}={4}{\left({15}\right)}\)

\(\displaystyle{10}{x}-{50}={60}\)

\(\displaystyle{10}{x}={60}+{50}\)

\(\displaystyle{10}{x}={110}\)

\(\displaystyle{\frac{{{10}{x}}}{{{10}}}}={\frac{{{110}}}{{{10}}}}\)

\(\displaystyle{x}={11}\)

The given ratios can be simplified further by doing cross product:

\(\displaystyle{\frac{{{10}}}{{{15}}}}={\frac{{{4}}}{{{x}-{5}}}}\)

\(\displaystyle{10}{\left({x}-{5}\right)}={4}{\left({15}\right)}\)

\(\displaystyle{10}{x}-{50}={60}\)

\(\displaystyle{10}{x}={60}+{50}\)

\(\displaystyle{10}{x}={110}\)

\(\displaystyle{\frac{{{10}{x}}}{{{10}}}}={\frac{{{110}}}{{{10}}}}\)

\(\displaystyle{x}={11}\)