tolong tulis cara y

50 × 2 = 100
60 × 3 = 180
70 × 5 = 350
80 × 2 = 160
90 × 7 = 630
100 × 5 = 500

Jumlah siswa
= 2 + 3 + 5 + 2 + 7 + 5
= 24

Rata rata
= ( 100 + 180 + 350 + 160 + 630 + 500 ) / 19
= 1920 / 24
= 80