Jawabanmu

2014-08-28T18:30:06+07:00
10 siswa = 55, artinya 10.55 = 550
jika ditambah 5 siswa menjadi 53?
10+5 = 15 siswa
(55.10+5x)/15 = 53
(550+5x)/15 = 53
550+5x = 53.15
550+5x = 795
5x = 795 - 550
5x = 245
x = 49