1. Let the original price be P.
2. GST is 10%, so the final price after GST is P + 0.1P = 1.1P.
3. Given the final price is \$137.50, we set up the equation:
1.1P = 137.50
4. Solving for P:
P = \frac{137.50}{1.1}
P = 125.00
5. Therefore, the original price before GST was \text{Original Price} = \$125.00.