问题 解答题
(1)3:8=x:2.4
(2)
1
10
1
8
=x:1
1
4
(3)x:4
3
4
=12:7
1
8
(4)0.3:
1
2
=
9
10
:x
(5)
7
10
=
0.4
x
(6)
3
4
:X=3:12
(7)8:x=6:3.
答案

(1)3:8=x:2.4,

8x=3×2.4,

8x÷8=7.2÷8,

x=0.9;

(2)

1
10
1
8
=x:1
1
4

1
8
x=
1
10
×1
1
4

1
8
x÷
1
8
=
1
8
÷
1
8

x=1;

(3)x:4

3
4
=12:7
1
8

7

1
8
x=4
3
4
×
12,

7

1
8
x÷7
1
8
=57÷7
1
8

x=8;

(4)0.3:

1
2
=
9
10
:x,

0.3x=

1
2
×
9
10

0.3x÷0.3=

9
20
÷0.3,

x=1.5;

(5)

7
10
=
0.4
x

7x=10×0.4,

7x÷7=4÷7,

x=

4
7

(6)

3
4
:X=3:12,

3x=

3
4
×12,

3x÷3=9÷3,

x=3;

(7)8:x=6:3,

6x=8×3,

6x÷6=24÷6,

x=4.

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