chemistry
posted by Jack .
How much ice is required to cool a 15.0oz drink from 71 F to 34 F, if the heat capacity of the drink is 4.18 J/g*C ? (Assume that the heat transfer is 100% efficient.)

Convert 15 oz to grams. I get about 425 but you should confirm that.
Convert 761F and 34F to celsius.
(mass ice x heat fusion) + [mass melted ice x specific heat H2O x (TfinalTinitial)] + [mass warm water x specific heat warm water x (TfinalTinitial)] = 0
Solve for x = mass ice. I ran this through the calculator (just once so you should check everything) and I get something like 108 g ice. Note that this assumes the ice is at a T of zero C. 
I got a very close answer, I just needed help with the steps, so thank you my friend.

425.243 g oz
26.1111c
0.555556 c 33
1.3794