Jawabanmu

2014-05-13T19:13:02+07:00
M = 2 kali
M= Si/So
2 = Si/20
Si = 40 cm

1/So + 1/Si = 1/f
1/20 + 1/40 = 1/f
2/40 + 1/40 = 1/f
3/40 = 1/f
f = 40/3 cm
f= 13,33 cm

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