Jawabanmu

2014-05-24T19:42:36+07:00
62 = 20.60 +70X \frac{x}{y} 20 + X
1240 + 62X = 1200 + 70X
40 = 8X
5 = X

Jadi tambahan anak 5 orang
4 2 4
Jawaban paling cerdas!
2014-05-24T19:45:00+07:00
Rata rata = (20 x 60) + ( n X 70)
                           20 + n
62 (20 + n)     = 1200 + 70 n
1240 + 62 n  = 1200 + 70 n
1240-1200 = 70 n - 62 n
40 = 8 n
n = 40/8= 5 orang
11 4 11