Formula applied
The exact method behind this answer
CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.
Catering = guests x per-head catering. Subtotal = catering + venue + photography + music + flowers + other. Total = subtotal x 1.10.- Apply the formulaCatering = guests x per-head catering. Subtotal = catering + venue + photography + music + flowers + other. Total = subtotal x 1.10.$28,050Catering $12,000.00; fixed vendor costs $13,500.00; subtotal $25,500.00 plus 10% contingency.