Combining the Magrib Prayer and its two supererogatory Rak`ahs with one Taslim

Q 1: A person entered the Masjid (mosque) to offer `Isha' (Night) Prayer. He offered five Rak`ahs (units of Prayer), so some Muslim brothers asked him why he had done so. His response was that he had not offered Maghrib (Sunset) Prayer, so he offered Maghrib Prayer (which is three Rak`ahs) and its two supererogatory Rak`ahs together with the same Taslim (salutation of peace ending the Prayer), following the example of Abu Al-Darda', the great Companion (may Allah be pleased with him). Is this permissible?

A: It is obligatory upon whoever offers the Maghrib Prayer and its supererogatory Salah (Prayer) as five Rak`ahs with one Taslim to offer the Magrib again as three Rak`ahs separately from its supererogatory Salah. Offering both of them with one Taslim is not permissible. Obligatory Salah and supererogatory Salah should be offered separately by concluding the obligatory Salah with Taslim.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.