Task: Question Answering
Input (English): Problem: barbata invests $ 2400 in the national bank at 4 % . how much additional money must she invest at 8 % so that the total annual income will be equal to 6 % of her entire investment ? 
Options: a ) 1200 , b ) 3000 , c ) 2400 , d ) 3600 , e ) 2450
Output (English): c