md journeymans practice test

i am trying to find a formula to figure out a practice question for a study guide and the question is how many btus must be added to one pound of ice at 32 degrees fahrenheit at sea level to change the entire pound of ice to one pound of water at the same temp. I know there is a formula just cant remember it can anyone help.

Maryland journeymens practice test

Thanks for the help I was making the question harder then it had to be and that's why this site is great thanks again to all who answered my question