Let's define \( x \) as the number of weekdays Lindsay practiced.
In this case, Lindsay practices:
- 50 minutes on Saturday
- 30 minutes on each weekday she practices
So, if she practices \( x \) weekdays, the total time she spends practicing on those days can be expressed as \( 30x \) (since she practices 30 minutes each weekday).
The total minutes she practiced in one week can be represented as: \[ 30x + 50 = 140 \]
Here, \( p = 30 \), \( q = 50 \), and \( r = 140 \).
This gives the equation in the form \( px + q = r \): \[ 30x + 50 = 140 \]