A sound source emits a wave of constant frequency \(f_0\) through air in which the speed of sound is \(v\). In Scenario 1, the source moves directly toward a stationary detector at speed \(v_s = 0.20v\), and the detector records an observed frequency \(f_1\). In Scenario 2, the source continues moving toward the detector at \(v_s = 0.20v\) while the detector simultaneously moves directly toward the source at speed \(v_d = 0.10v\), recording an observed frequency \(f_2\). What is the ratio \(f_2 / f_1\)?