Answer:
114 red marbles
Step-by-step explanation:
red: black: total
19 1 19+1 = 20
We have 120 marbles
120/20 = 6
Multiply each by 6
red: black: total
19 *6 1*6 20*6
114 6 120
To find the percent increase you need to first find how much the price went up: 2.65 - 2.4 = .25 Now divide .25 by the original price.
Answer:

Step-by-step explanation:
You can solve this equation with the quadratic formula which is:

All you need to do is rearrange the equation (add
to both sides and then multiply both sides by 2) to get:

From this new equation, we can easily see that a = 2, b = -5, and c = 11 AND you don't have to work with as many fractions. Substitute the values for a, b, and c into the quadratic formula to get:

That simplifies to:

Which simplifies even further to:

Which gets you:

P.S. The plus-minus sign wasn't working for me, so I had to just write, "+or-". I hope that didn't make it too confusing for you.
P.P.S. Hope this helps :) Don't forget to mark Brainliest if it did.