Jawabanmu

2014-04-04T18:53:07+07:00
M1 . c1. ( ta -t1 ) = m2. c2. ( t2- ta )
80 . (60 - t1) = 120 ( 90 - 60)
4800 - 80t1 = 3600
80 t1 = 1200
t1 = 15
1 1 1