plis dong dijawab yg a sma yg b

46. a) rata-rata nilai ulangan yg hilang
adalah: {(36 × 7,2) - (30 × 7,0)} ÷ 6
= (259,2 - 210) ÷ 6
= 49,2 ÷ 6
= 8,2

b) misal wanita = x dan pria = y
x + y = 30 ----> x = 30 - y

168x + 158y = 165×30
168x + 158y = 4.950
168(30-y) + 158 y = 4.950
5.040 - 168y + 158y = 4.950
5.040 - 4.950 = 10y
90 = 10y
y = 90 ÷ 10
y = 9

x + y = 30
x + 9 = 30
x = 30 - 9
x = 21

jadi jumlah siswa wanita = x = 21 orang

yg B saya blum bisa jwabnya cuma yg A
semoga membantu