Answer:
One of the negatives must go
Step-by-step explanation:
If I've read this correctly, it looks like this.

If that is correct, then the first step is to put the top part of the denominator over 3x
The next part is to flip a three tier fraction. I'm afraid I have to show what happens. My latex is not that strong.
What you get is

This is just about your final answer. You could write it as

When you go into this problem, you want to figure out your marble ammount to 50 so in this case we will say C for color and 50 for the total ammount of marbles.
We know 15 are pink, 8 are black, 2 are green, 18 are clear, and 7 are striped
15P/50
8B/50
2G/50
18C/50
7S/50 for a total of 50 marbles
Now we use the chart to decide our awnsers
A. We know our propability of drawing a green and clear is 20/50 which if we simplify is a 2/5 ratio. If We put this in perspective 2/5 is rare and is unlikley to even.
B. We know a striped marble is 18/50 or 1.8/5 ratio which is mainly unlikely
C. We have 23/50 marbles that are black and pink, our propability is about 2.3/5 and gives us an even chance to get one of these
D. We know we have 33/50 marbles that are pink and clear and gives us a 3.3/5 chance of getting one of these and gives us an even to likely chance of getting one of these.
E. If we have a total of 17 marbles in these 3 colors, we have a 1.7/5 chance of getting one of these and is probably impossible to unlikey.
Answer:
it's either B=6.25-1.25r or it's r=5-0.8b