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 20 % and that of tea dropped by 10 % . 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 ) 45 , b ) 40 , c ) 35 , d ) 47.61 , e ) 30
Output (English): d