x:4/1=2/3:3/5
3/5x=8/3
x=8/3÷3/5
x=40/9
x:4=0.35:0.6
0.6x=1.4
x=7/3
2/3:5/6=x:8/9
5/6x=16/27
x=32/45
x:3/8=15:0.8
0.8x=45/8
x=225/32