The answer is B.   Because there are 8 ribbons in all. 1 ribbon is black. so the equation would be 1/8. Assuming you don't draw the black ribbon on the first try, then you would try again. The second time you draw a ribbon you don't put the ribbon you drew back in. That means there are only 7 ribbons the second time. The 1 black ribbon is still in the bag than the equation would be 1/7. Then you add the two together. So it would be 1/8 + 1/7 = 1/15. Remember to only add the bottom numbers. not the top ones unless they are different colors or objects.
        
             
        
        
        
Answer:
Its either answer B. or D. Sorry if I'm wrong and I hope this sorta helps.
 
        
             
        
        
        
Answer:
x = 2, y = 7, z = 12
Step-by-step explanation:
x + y - z = -3 (1)
3x - y + z = 11 (2)
x - 4y + z = -14 (3)
add (1) and (2)
4x = 8 x = 2
add (1) and (3)
2x - 3y = -17
2(2) - 3y = -17
-3y = -17 - 4
-3y = -21
y = 7
Find z using any equation 
x + y - z = -3
2 + 7 - z = -3
9 - z = -3
z = 12