2x+3×0.9=24.7
2x=24.7-3×0.9=22
x=11
(3/4):x=(2/5):24
(2/5)x=(3/4)×24=18
x=18×5/2=45
2X+3x0.9=24.7
解:2X+2.7=24.7
2X=24.7-2.7
2X=22
X=11
3/4:X=2/5:24
解:3/4x1/X=2/5x1/24
1/X=1/60÷3/4
1/X=1/60x4/3
1/X=1/45
X=45