I have not seen unit rate in a while, but I believe it means 1 unit. Therefore it is looking for the price of 1kg of pecans. Since 1÷0.5 = 2, the price of 1 kilogram of pecans is 7.75×2=$15.50
The unit rate means 1 unit of the current placeholder. In this situation, it is kilograms. To find the unit rate, you would multiple 7.75 by 2, giving you the answer of 15.5.