tolong ya sama caranya

tinggi rata rata 8 siswa =
[tex]170 = \frac{x}{8} \\ x = 170 \times 8 = 1360[/tex]
tinggi rata rata 12 siswa =
[tex]165 = \frac{x}{12} \\ x = 165 \times 12 = 1980[/tex]
rata rata seluruh siswa
[tex] \frac{1360 + 1980}{20} = 167[/tex]
jawabannya C