A 0.300 kg iron horseshoe that is initially at 550°C is dropped into a bucket containing 19.4 kg of water at 21.1°C. What is the final equilibrium temperature (in °C)? Neglect any heat transfer to or from the surroundings. Do not enter units.

I'm taking (specific heat of water*mass of water)+(specific heat of iron*mass of iron) and keep getting the wrong answer. Please help!