To solve the system of equations:
- \( x + 3y = 15 \) (Equation 1)
- \( 3x + 2y = 10 \) (Equation 2)
We can use the substitution or elimination method. Let's solve it using the substitution method by expressing \( x \) from Equation 1.
From Equation 1:
\[ x = 15 - 3y \]
Now, we substitute \( x \) in Equation 2:
\[ 3(15 - 3y) + 2y = 10 \]
Expanding this gives:
\[ 45 - 9y + 2y = 10 \]
Combining like terms:
\[ 45 - 7y = 10 \]
Now, isolate \( y \):
\[ -7y = 10 - 45 \]
\[ -7y = -35 \]
Dividing both sides by -7:
\[ y = 5 \]
Thus, the value of \( y \) for the solution to the system is:
\[ y = 5 \]