Tolong dijawab ya PAKAI CARA thx :)

[tex] = \frac{(2 \times 4) + (3 \times 4) + (4 \times 5) + (5 \times 4) + (6 \times 3)}{4 + 4 + 5 + 4 + 3} [/tex]
[tex] = \frac{8 + 12 + 20 + 20 + 18}{20} [/tex]
[tex] = \frac{78}{20} \\ = 3.9[/tex]