1. **State the problem:** We have a bag with green, red, and blue marbles. The number of marbles for each color is given by expressions involving $x$ and $y$:
- Green: $4x - y + 3$
- Red: $x + 3y - 5$
- Blue: $x + y + 11$
We know the probability of picking a green marble is $\frac{1}{5}$ and $x=3$. We need to find $y$.
2. **Write the formula for probability:**
$$\text{Probability of green} = \frac{\text{Number of green marbles}}{\text{Total number of marbles}} = \frac{1}{5}$$
3. **Substitute the expressions and $x=3$:**
Number of green marbles:
$$4(3) - y + 3 = 12 - y + 3 = 15 - y$$
Number of red marbles:
$$3 + 3y - 5 = 3 + 3y - 5 = 3y - 2$$
Number of blue marbles:
$$3 + y + 11 = y + 14$$
Total marbles:
$$ (15 - y) + (3y - 2) + (y + 14) = 15 - y + 3y - 2 + y + 14 = (15 - 2 + 14) + (-y + 3y + y) = 27 + 3y$$
4. **Set up the probability equation:**
$$\frac{15 - y}{27 + 3y} = \frac{1}{5}$$
5. **Cross multiply and solve for $y$:**
$$5(15 - y) = 1(27 + 3y)$$
$$75 - 5y = 27 + 3y$$
$$75 - 27 = 3y + 5y$$
$$48 = 8y$$
$$y = \frac{48}{8} = 6$$
6. **Final answer:**
$$y = 6$$
This means when $x=3$, the value of $y$ that satisfies the probability condition is 6.
Marble Probability
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