Two strings \((A,B)\) having linear densities \(\mu_A = 2\times 10^{-4}~\text{kg/m}\) and \(\mu_B = 4\times 10^{-4}~\text{kg/m}\) and lengths \(L_A =2.5~\text{m}\) and \(L_B = 1.5~\text{m}\) respectively are joined. Free ends of \(A\) and \(B\) are tied to two rigid supports \(C\) and \(D\), respectively creating a tension of \(500~\text{N}\) in the wire. Two identical pulses, sent from \(C\) and \(D\) ends, take time \(t_1\) and \(t_2\), respectively, to reach the joint. The ratio \(\dfrac{t_1}{t_2}\) is:
1. \(1.08\)
2. \(1.90\)
3. \(1.67\)
4. \(1.18\)