a watch was sold at a loss of 36 % . if it was sold for rs . 140 more , there would have been a gain of 4 % . what is the cost price ?
"64 % 104 % - - - - - - - - 40 % - - - - 140 100 % - - - - ? = > rs . 350 answer : a"
divide(multiply(140, const_100), subtract(add(const_100, 4), subtract(const_100, 36)))