gimana cara soal cerita ini

3m+4j=120.000 (2) 6m+8J=240.000
2m+5j=115.000 (3) 6m+15J=345.000
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7j=105.000
j=15.000
3m+4x15000=120000
3m+60000=120000
3m=120000-60000
m=60000:3
m=20000


nisa
4x20000+3x15000=200000
80000+45000=200000
nisa=200000-125000=75000
jawabanya 75.000