Question

4道解比例①30:4=X:10 ② 0.12:4=0.6:X ③ 2/3：X+2:5 ④X：4=0.3:5

Answer 1

①30:4=X:10

4x=30×10

4x=300

x=300÷4

x=75

② 0.12:4=0.6:X

0.12x=4×0.6

0.12x=2.4

x=2.4÷0.12

x=20

③ 2/3：X=2:5

2x=2/3×5

2x=10/3

x=10/3÷2

x=5/3

④X：4=0.3:5

5x=4×0.3

5x=1.2

x=1.2÷5

x=0.24