To represent Maria's savings in the form of the equation \(px + q = r\):
- \(p\) is the amount she saves each week, which is $19.
- \(x\) is the number of weeks.
- \(q\) is her initial amount, which is $50.
- \(r\) is the target amount she wants to reach, which is $259.
Putting these values into the equation, we get:
\[ 19x + 50 = 259 \]
So, the correct response is:
19x + 50 = 259 (19 x plus 50 equals 259)