Ada yang tau?

<p>Dik :&nbsp;<br>Jumlah siswa = 20<br>Rata-rata nilai rapor = 89,9<br>Siswa baru = 1 orang&nbsp;<br>Rata-rata nilai rapor naik setelah ada siswa baru = 0,3<br>Dit : Rata-rata nilai rapor siswa baru =..?<br>Jwb :&nbsp;<br><strong>Pertama</strong>, hitung nilai data keseluruhan (jumlah seluruh rata-rata nilai rapor setiap siswa) sebelum siswa baru datang<br>Rata-Rata = Jumlah nilai data / Jumlah siswa<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 89,9 = x / 20<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; x = 89,9 x 20<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; x = 1.798</p><p><strong>Kedua</strong>, hitung nilai data (rata-rata nilai rapor) siswa baru<br>Rata-Rata = Jumlah nilai data / Jumlah siswa<br>89,9 + 0,3 = 1.798 + x / 20+1<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 90,2 = 1.798 + x / 21<br>&nbsp;&nbsp; 1.798 + x = 90,2 x 21<br>&nbsp;&nbsp; 1.798 + x = 1.894,2<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; x = 1.894,2 - 1.798<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; x = 96,2<br><strong>Jadi, Rata-Rata Nilai Rapor Peraih Medali Emas Olimpiade Matematika (siswa baru) tersebut adalah 96,2</strong></p><p><strong>Jawabannya A. 96,2</strong></p>