Jumlah uang ririn rika dan aldi 420.000.uang rika 2/3 uang ririn dan uang ririn 4/5 uang aldi.berapa uang mereka masing masing

Ririn = 4/5z
Rika = 2/3 . 4/5z = 8/15z 
Aldi = z 

→ Ririn + Rika + Aldi = 420.000

4/5z + 8/15z + z = 420.000
12/15z + 8/15z + 15/15z = 420.000
35/15 z = 420.000
7/3 z = 420.000
z = 420.000 : 7/3
z = 420.000 x 3/7
z = 60.000 x 3
z = 180.000

→RIRIN
= 4/5 z
= 4/5 . 180.000
= 4 x 36.000
= 144.000

→RIKA
= 8/15 . z
= 8/15 . 180.000
= 8 x 12.000
= 96.000

→ALDI
= z 
= 180.000