The pair of linear equations x + 2y = 3 and 5x + 10y = 15 has:

Comparing the coefficients: $\frac{a_1}{a_2} = \frac{1}{5}$, $\frac{b_1}{b_2} = \frac{2}{10} = \frac{1}{5}$, and $\frac{c_1}{c_2} = \frac{3}{15} = \frac{1}{5}$. Since $\frac{a_1}{a_2} = \frac{b_1}{b_2} = \frac{c_1}{c_2}$, the equations are dependent and have infinitely many solutions.