tolong bantuannya !!

Kelas 9 Matematika
Bab Statistika

x = (124 + 248 + 372 + .... + 1.116)/(4 + 8 + 12 + ... + 36)
x = 124 (1 + 2 + 3 + ... + 9)/(4 (1 + 2 + 3 + ... + 9))
x = 124/4
x = 31