x:3=7/8:1/49:x=4.5/0.81/6:2/5=1/2:2x3/8:x=5%:0.6

x:3=7/8:1/49:x=4.5/0.81/6:2/5=1/2:2x3/8:x=5%:0.6
x:3=7/8:1/4
9:x=4.5/0.8
1/6:2/5=1/2:2x
3/8:x=5%:0.6

x:3=7/8:1/49:x=4.5/0.81/6:2/5=1/2:2x3/8:x=5%:0.6
x:3=7/8:1/4
1/4X=21/8
X=21/4
9:x=4.5/0.8
4.5X=7.2
X=1.6
1/6:2/5=1/2:2x
1/3X=1/5
X=3/5
3/8:x=5%:0.6
5%X=9/40
X=9/2

解1题：
x×1/4=3×7/8
x=21/8÷(1/4)
x=21/2
2题：
9：x=4.5:0.8
4.5x=9×0.8
4.5x=7.2
x=7.2÷4.5
x=1.6
3题：
2x×1/6=2/5×1/2
x×1/3=1/5
x=1/5÷(1/3)
x=3/5
4题：
x×5℅=0.6×3/8
x×0.05=0.225
x=0.225÷0.05
x=4.5