There were 5 of the 15 in the simulation that used a coupon. To find the probability you just divide 5 by 15
P(=>4) = 5/15 = 1/3 - probability of 4 or more
Most of the information's are already given in the question. It is important to understand the language of the problem for solving the problem. Once the language is understood, then solving the problem is easy.
Let us assume the number of black jelly beans = x
Number of yellow jelly beans = y
Then from the question we can get to a equation.
3x - 7 = y
We also know from the question that
x + y = 225
x + 3x -7 = 225
4x = 225 + 7
4x = 232
x = 232/4
= 58
So Cassidy has 58 black jelly beans out of the total of 225 jelly beans
Since all the sides add up to 10x+2, that means that 10x-2-<side1>-<side2>=<side3>. Plugging it in, we have 10x-2-5x-(2x+9)=side3, and 5x-2-(2x+9)=side3, then expanding it to 5x-2-2x-9=3x-11=side3
First lets simplify the first term and yield (2a)
The second term:
1. 2a * (-1/2) = -a
2. -a + a = 0
Now we have simplified both terms to: (2a) (0)
Anything multiplied by 0 is 0, so the answer is also 0.