Task: Question Answering
Input (English): Problem: a car dealership has 40 cars on the lot , 10 % of which are silver . if the dealership receives a new shipment of 80 cars , 25 % of which are not silver , what percentage of total number of cars are silver ? 
Options: a ) 15 % , b ) 18 % , c ) 20 % , d ) 21 % , e ) 22 %
Output (English): c