No 10 ?? Apa , yang tau nanti saya kasih terbaik terimakasih...

X=f1 x1 + f2 x2 + f3 x3 + f4 x4 + f5 x5 + f6 x6 + f7 x7 /f1+f2+f3+f4+f5+f6+f7
  =40*2 + 41*4 + 42*6 + 43*10 + 44*5 + 45*3 + 46 *5/2+4+6+10+5+3+5
  =80+164+252+430+220+135+230/35
  =1511/35
  =43,71

Semoga Membantu

40 x 2 = 80
41 x 4 = 164
42 x 6 = 252
43 x 10 = 430
44 x 5 = 220
45 x 3 = 135
46 x 5 = 230


80 + 164 + 252 + 430 + 220 + 135 + 230/35 = 1511/35 = 43,71