In a music collection, there are 100 songs with an average length of exactly 180 seconds. One song is added and the new average length is exactly 181 seconds. How long, in seconds, was the added song?
+36915 total songs length /100 = 180
total songs length = 18 000
add one song
total songs length2 / 101 = 181
18281
18281 - 18000 = 281 seconds
