dacid obtained 91 , 65 , 82 , 67 and 85 marks ( out of 100 ) in english , mathematics , physics , chemistry and biology . what are his average marks ?
"average = ( 91 + 65 + 82 + 67 + 85 ) / 5 = 78 answer : b"
divide(add(add(add(add(91, 65), 82), 67), 85), divide(const_10, const_2))