4. The difference between twice a number and half the number is 30. What is the number?
Help me please

20

Step-by-step explanation:

let the number be n then twice the number is 2n and half the number is n

Then the difference is

2n - n = 30 ( multiply through by 2 to clear the fraction )

4n - n = 60, that is

3n = 60 ( divide both sides by 3 )

n = 20

answer

a the answer hopes this

step-by-step explanation:

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional