Task: Question Answering
Input (English): Problem: in what ratio must rice of rs . 25 per kg be mixed with rice of rs . 12 per kg so that cost of mixture is rs . 20 per kg ? 
Options: a ) 8 : 5 , b ) 5 : 8 , c ) 20 : 25 , d ) 12 : 20 , e ) 25 : 12
Output (English): a