Jawabanmu

2014-03-26T18:07:05+07:00
M= s'/s 
3= s'/12
s' = 36

1/f = 1/s' +1/s
1/f = 1/36 + 1/12
1/f = 1/36 + 3/36
1/f = 4/36
f = 9
1 5 1