3 6 7 4
+ 6 7 8 9
~~~~~~~
10 4 6 3
Before I answer the question i am going to start with the blue Marble you would have a 1/8 chance of drawing the blue marble from the box and after that you would have a 3/7 of drawing a white marble because you did not replace the blue marble and I hope this help.
Answer:
w = 4
Step-by-step explanation:
13w-8w =20
Combine like terms
5w = 20
Divide each side by 5
5w/5 = 20/5
w = 4