Dari beberapa kali ulangan Matematika, seorang anak memiliki nilai 5,6,4,7.Jika anak tersebut diberi satu ulangan lagi, berapakah nilai ulangan anak tersebut a

Bab Statistika
Matematika SMP Kelas VII

nomor 1

rata-rata = 6
(5 + 6 + 4 + 7 + a)/5 = 6
22 + a = 6 . 5
a = 30 - 22
a = 8

nomor 2
(5 + 6 + 4 + 7 + a)/5 = 5,5
22 + a = 5,6 . 5
a = 28 - 22
a = 6

[tex]x1 = 5 + 6 + 4 + 7 = 22 \div 4 = 5.5 \\ x2 = ... \\ f1 = 4 \\ f2 = 1 \\ x \: gab = 6 \: dan \: 5.6 \\ \\ x \: gab = \frac{x1f1 + x2f2}{f1 + f2} \\ 6 = \frac{5.5(4) + x2}{5} \\ 6 = \frac{22 + x2}{5} \\ 6 \times 5 = 22 + x2 \\ 30 = 22 + x2 \\ x2 = 30 - 22 \\ x2 = 8 \\ \\ 5.6 = \frac{5.5(4) + x2}{5} \\ 5.6 = \frac{22 + x2}{5} \\ 5.6 \times 5 = 22 + x2 \\ 28 = 22 + x2 \\ x2 = 28 - 22 \\ x2 = 6[/tex]
Maaf Kalau Salah