Task: Question Answering
Input (English): Problem: the perimeter of an equilateral triangle is 45 . if one of the side is the side of an isoceles triangle of perimeter 40 then what is the lenght of base of isoceles triangle . 
Options: a ) 10 units , b ) 20 units , c ) 30 units , d ) 40 units , e ) 15 units
Output (English): a