Answer: 0.8 or 80%
Step-by-step explanation:
First find the total number of marbles:
10 + 15 + 25 = 50 marbles total
To find the number of marbles that are not black:
15 + 25 = 40 marbles that are not black
Set up ratio:
= 0.8 or 80%
4/d = 2/6
4*6= 2*d
24=2d
d=12
(r-3)/10=r/13
13(r-3)=10r
13r-39=10r
3r=39
r=13
The answer is
x = 1 and y = -3
<span>[1] 6x-9=y
[2] y=-3x</span>