问题 解答题
解比例.
x:42=
5
7
:10
x
2.4
=
15
0.8
1
2
:x=
3
4
:6.
答案

(1)x:42=

5
7
:10,

       10x=42×

5
7

       10x=30,

   10x÷10=30÷10,

         x=3;

(2)

x
2.4
=
15
0.8

      0.8x=2.4×15,

      0.8x=36,

 0.8x÷0.8=36÷0.8,

         x=45;

(3)

1
2
:x=
3
4
:6,

      

3
4
x=
1
2
×6,

      

3
4
x=3,

  

3
4
3
4
=3÷
3
4

         x=4.

选择题
综合