Question: Sedaka's Back is a compilation album that included songs that were turned into hits by other artists such as "Solitaire" by an American vocal and instrumental duo that recorded how many albums?   

Context articles: The Carpenters
The Very Best of Neil Sedaka
My Yiddishe Momme: Neil Sedaka at Chequers
The Belle Brigade
The Other Side of Me (Andy Williams album)
The Many Sides of Neil Sedaka
Sedaka's Back
Steppin' Out (Neil Sedaka album)
Neil Sedaka: All Time Greatest Hits, Volume 2
Neil Sedaka: Italiano

The Carpenters were an American vocal and instrumental duo consisting of siblings Karen (1950-1983) and Richard Carpenter (b. 1946).
 Producing a distinctively soft musical style, which combined Karen's contralto vocals with Richard's arranging and composition skills, they became one of the best-selling music artists of all time.
 During their 14-year career, the Carpenters recorded 11 albums, 31 singles, five television specials, and a short-lived television series.
The Very Best of Neil Sedaka is a 2001 compilation album issued by RCA Records as part of their commemorative "100th Anniversary" series of albums celebrating their biggest stars.
 This album features some of Sedaka's best-known hits during his days with RCA, recorded from 1958-1963.
My Yiddishe Momme: Neil Sedaka at Chequers is a 1966 Australian compilation album containing the works of American pop singer Neil Sedaka.
 Eight of the songs on this album had been previously released earlier in Sedaka's career, but it included four new recordings produced in RCA's Australian studios in Sydney, Australia, following a concert Sedaka had given at Sydney's famous Chequers nightclub.
 It was released on RCA's Australian label.
The Belle Brigade is an American vocal and instrumental duo from Los Angeles, CA, consisting of siblings Barbara Gruska (born c. 1983) on guitar, drums, and vocals, and Ethan Gruska (born c. 1989) on guitar, piano, and vocals.
 The duo released its first album, "The Belle Brigade", in 2011 to positive critical response.
The Other Side of Me is an album by American pop singer Andy Williams that was released in the summer of 1975 by Columbia Records and included the 1973 recording of "Solitaire" from his album of the same name alongside 10 original recordings, four of which were also by "Solitaire" composer Neil Sedaka.
 After unsuccessful attempts to leave behind the formulaic album genre of easy listening covers of pop hits, "The Other Side of Me" offered a compromise by filling half of the sides with material that was popularized by other artists and the other half with either new or obscure selections.
The Many Sides Of Neil Sedaka is a 1978 compilation album released by RCA Victor Records containing the works of pop singer Neil Sedaka.
 The album contains some of Sedaka's lesser-known works in the period from 1958-1965, although three of the songs on the album were charting hits at the time of their original release.
Sedaka's Back is a compilation album by American singer-songwriter Neil Sedaka.
 The record, composed of selections from his previous three albums, which had been released only in the UK, was released on Elton John's label, The Rocket Record Company, in 1974.
 Three singles were released from this album: "Laughter in the Rain" (a #1 hit), "The Immigrant" (dedicated to John Lennon) and "That's When The Music Takes Me."
 The latter two songs were both Top 40 hits.
 Also included were songs that were turned into hits by other artists: "Solitaire" (The Carpenters) and "Love Will Keep Us Together" (The Captain & Tennille).
 The album reached No. 23 on the US Billboard album charts and was certified Gold for shipping half a million sales.
Steppin' Out is a 1976 album containing the works of Neil Sedaka.
 In America it was the third and final album of a trilogy of albums issued by The Rocket Record Company.
 (Rocket would issue a compilation album, "Neil Sedaka's Greatest Hits", in 1977; but it contained no new material.)
 Outside America "Steppin' Out" was issued on the Polydor label.
 In 1998 Varese Serabande reissued "Steppin' Out" and included four bonus tracks.
Neil Sedaka: All Time Greatest Hits, Volume 2 is a compilation album containing the works of American pop singer Neil Sedaka.
 The songs featured are some of Sedaka's lesser-known songs from his days with RCA Victor from 1958–1966, songs that were not included on the 1988 album "Neil Sedaka: All Time Greatest Hits".
 The album was released in 1991 by RCA Records.
Neil Sedaka: Italiano is a 1964 compilation album containing twelve of Neil Sedaka's Italian-language recordings.
 It was released in Italy by RCA Victor's Italiana studios.
 Of the twelve songs on the album, six were recorded by Sedaka in English.
 A seventh song on the album, "A 16 Anni Tu Vuoi Amare", is an Italian-language version of Andrea Carroll's 1963 hit, "It Hurts To Be Sixteen".