Béla Bartók
Béla Viktor János Bartók ( ; , ] ; 25 March 1881 – 26 September 1945) was a Hungarian composer, pianist, and ethnomusicologist. He is considered one of the most important composers of the 20th century; he and Franz Liszt are regarded as Hungary's greatest composers . Through his collection and analytical study of folk music, he was one of the founders of comparative musicology, which later became ethnomusicology.
Béla Bartók
Bartók was born in the Banatian town of Nagyszentmiklós in the Kingdom of Hungary (present-day Sânnicolau Mare, Romania) on 25 March 1881. On his father's side, the Bartók family was a Hungarian lower noble family, originating from Borsodszirák, Borsod. His paternal grandmother was a Catholic of Bunjevci origin, but considered herself Hungarian . Bartók's father was also named Béla. Bartók's mother, Paula (née Voit), had ethnic German roots but spoke Hungarian fluently . A native of Turócszentmárton (present-day Martin, Slovakia) , she also had Hungarian and Slavic ancestry. 
Richard Strauss
Strauss's compositional output began in 1870 when he was just six years old and lasted until his death nearly eighty years later. While his output of works encompasses nearly every type of classical compositional form, Strauss achieved his greatest success with tone poems and operas. His first tone poem to achieve wide acclaim was "Don Juan", and this was followed by other lauded works of this kind, including "Death and Transfiguration", "Till Eulenspiegel's Merry Pranks", "Also sprach Zarathustra", "Don Quixote", "Ein Heldenleben", "Symphonia Domestica", and "An Alpine Symphony". His first opera to achieve international fame was "Salome" which used a libretto by Hedwig Lachmann that was a German translation of the French play "Salomé" by Oscar Wilde. This was followed by several critically acclaimed operas with librettist Hugo von Hofmannsthal: "Elektra", "Der Rosenkavalier", "Ariadne auf Naxos", "Die Frau ohne Schatten", "Die ägyptische Helena", and "Arabella". His last operas, "Daphne", "Friedenstag", "Die Liebe der Danae" and "Capriccio" used libretti written by Joseph Gregor, the Viennese theatre historian. Other well-known works by Strauss include two symphonies, lieder (especially the "Four Last Songs"), the Violin Concerto in D minor, the Horn Concerto No. 1, Horn Concerto No. 2, his Oboe Concerto and other instrumental works such as "Metamorphosen".
Richard Strauss
Strauss was also a prominent conductor in Western Europe and the Americas, enjoying quasi-celebrity status as his compositions became standards of orchestral and operatic repertoire. He was chiefly admired for his interpretations of the works of Liszt, Mozart, and Wagner in addition to his own works. A conducting disciple of Hans von Bülow, Strauss began his conducting career as Bülow's assistant with the Meiningen Court Orchestra in 1883. After Bülow resigned in 1885, Strauss served as that orchestra's primary conductor for five months before being appointed to the conducting staff of the Bavarian State Opera where he worked as third conductor from 1886–1889. He then served as principal conductor of the Deutsches Nationaltheater and Staatskapelle Weimar from 1889–1894. In 1894 he made his conducting debut at the Bayreuth Festival, conducting Wagner's "Tannhäuser" with his wife, soprano Pauline de Ahna, singing Elisabeth. He then returned to the Bavarian State Opera, this time as principal conductor, from 1894–1898, after which he was principal conductor of the Berlin State Opera from 1898–1913. From 1919–1924 he was principal conductor of the Vienna State Opera, and in 1920 he co-founded the Salzburg Festival. In addition to these posts, Strauss was a frequent guest conductor in opera houses and with orchestras internationally.

Question: Who passed away first Richard Strauss or Béla Bartók ?
Answer: Béla Viktor János Bartók