Task: Question Answering
Input (English): Problem: the prices of tea and coffee per kg were the same in june . in july the price of coffee shot up by 10 % and that of tea dropped by 20 % . if in july , a mixture containing equal quantities of tea and coffee costs 50 / kg . how much did a kg of coffee cost in june ? 
Options: a ) 50 , b ) 45 , c ) 52.63 , d ) 40 , e ) 35
Output (English): c