24/x-20/1.2x=20
28.8/1.2x-20/1.2x=20
8.8/1.2x=20
x=8.8/1.2÷20
x=11/30
2640/x-2640/2x=2×60
2640/x-1320/x=120
1320/x=120
x=1320÷120
x=11
24/x-20/1.2x=20
28.8/1.2x-20/1.2x=20
8.8/1.2x=20
x=8.8/1.2÷20
x=11/30
2640/x-2640/2x=2×60
2640/x-1320/x=120
1320/x=120
x=1320÷120
x=11