Question 137268
Check your temperature scales. 
What state is water in when it is 10 degrees Celsius? Liquid, a cold glass of water, coming out of the tap. 
What state is water in when it is 10 degrees Fahrenheit? Solid (Ice), like in the freezer. 
The coin in the 10 degrees Celsius bucket will reach the bottom first. 
The coin in the 10 degrees Fahrenheit bucket will sit on top of the ice.