Task: Question Answering
Input (English): Problem: in one alloy there is 10 % chromium while in another alloy it is 6 % . 15 kg of the first alloy was melted together with 35 kg of the second one to form a third alloy . find the percentage of chromium in the new alloy . 
Options: a ) 7.2 % , b ) 9 % , c ) 9.2 % , d ) 8.6 % , e ) 8.4 %
Output (English): a