Jawabanmu

2014-03-09T18:15:37+07:00
2014-03-09T18:40:21+07:00
M.c.Δt              = m.c.Δt
(200)(1)(t-30)= 100(1)(90-t)
200t - 6000 = 9000 - 100t
300t = 15000
t = 50
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