The ratio of blue to red marbles is 2 to 5. if i have a total of 25 marbles , how many would it be blue.

The number of blue marbles is 10

Step-by-step explanation:

The correct question is

The ratio of blue to red marbles is 2 to 5. If I have a total of 35 marbles , how many would it be blue

Let

x -----> the number of blue marbles

y -----> the number of red marbles

we know that

----> ---> equation A

----> equation B

Substitute equation A in equation B

Solve for y

Find the value of x

therefore

The number of blue marbles is 10

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