Answer: 12 blue marbles
Step-by-step explanation: Set up a proportion.
4/5 = x/15
Solve for x, the number of blue marbles. Cross multiply. You will get 60 = 5x
Divide by 5 on each side.
x = 12
There are 12 blue marbles.
The answer your looking for is 10x
If you use the first answer, the equation becomes 2x + 2y = 16. You could subtract this from equation Q to eliminate x.
The second answer makes equation P -2x - 2y = -16. You could add this to equation Q to eliminate x. You can use both of these methods to eliminate the x term, but if you can only choose one, you should choose the second option.
No the answer to the solution would be 7
