Ten songs from BTS’ fifth studio album “Arirang” remained on Billboard’s Hot 100, led by “Swim” at No. 2. On the chart dated April 11, the lead single slid down a rung after a chart-topping debut the previous week, which saw 13 of 14 tracks spread among the Hot 100. The album is also spending a second week atop the Billboard 200, in a first for a K-pop group or artist. The septet is embarking on a world tour named after the LP on Thursday with three nights of shows in Goyang, Gyeonggi Province.