[tabularasa]

I have tried this problem so many times today, and I have yet to receive a response from my professor and my TA.

Calculate the entropy change that occurs when a 27.5 gram piece of ice at 0deg C is placed into a styrofoam cup containing 126.0 grams of water at a temperature of 77.0deg C. Assume that there is no loss or gain of heat to or from the surroundings. Enter your answer in J/K as a number in scientific notation without units. The heat of fusion of water is 333 J/g. Assume that the specific heat of H2O(l) is constant at 4.184 JK-1g-1.

(27.5 g ice)(333J/g) + (27.5g)(4.184 J/k*g)(x-273K) =
(126.0g water)(4.184 J/K*g)(350K-x)

I got x= 326.7K

I solved delta S for the ice:
(27.5 g)(333 J/g) = 9157.5J
and I took this number and divided by the melting point of water
9157.5/ 273K = 33.54J/K

then  I solved for the entropy of the warming water
dS= n*C ln (Tf/ Ti)
dS= (27.5g)(4.184 J/K*g)(ln (326.7K/273K)
dS= 20.66 J/K

then I solved for the entropy of the cooling water
dS= n*C ln (Tf/Ti)
dS= (126.0g)(4.184J/K*g)(326.7K/350K)
dS= -36.318 J/K

and I added these all together to get 20.02, and still got the problem wrong (it's computerized). Please help me, this is due by 8am Saturday morning and it's my only problem left!