Light from a source emitting two wavelengths λ1 and λ2 is allowed to fall on Young's double-slit apparatus after filtering one of the wavelengths. The position of an interference maximum is noted. When the filter is removed, both wavelengths are incident and maximum intensity is produced where the fourth maximum occurred previously. If the other wavelength is filtered, the third maximum is found at the same location. What is the ratio of the wavelengths?
(1) 32
(2) 23
(3) 43
(4) 34