The Initial Value Illusion
A rental company charges a one-time insurance fee plus a daily rate. The total cost \(C\) for \(d\) days is given by \(C = 15(d-2) + 50\). What is the initial insurance fee?
🚩 The Trap
Assuming the constant "50" is always the starting value. Here, the expression is shifted.
✅ The Practix Shortcut
Initial value is at \(d=0\). Plug it in:
\(C = 15(0-2) + 50\)
\(C = -30 + 50 = 20\).
The constant 50 includes 2 days of rental already!
Answer: 20.