For mass m1, period is T
∴ T = 2π\(\sqrt{\frac{m_1}{k}}\)
For mass m2, period is 2T
∴ 2T = 2π\(\sqrt{\frac{m_1+m_2}{k}}\)
∴ 2T/T = 2 = \(\sqrt{\frac{m_1+m_2}{m_1}}\)
∴ \(\frac{m_1+m_2}{m_1}\) = 4
∴ \(\frac{m_2}{m_1}\) = 3
∴ \(\frac{m_1}{m_2}\) = \(\frac{1}{3}\)