a watch was sold at a loss of 10 % . if it was sold for rs . 540 more , there would have been a gain of 8 % . what is the cost price ?
"90 % 108 % - - - - - - - - 18 % - - - - 540 100 % - - - - ? = > rs . 3000 answer : c"
divide(multiply(540, const_100), subtract(add(const_100, 8), subtract(const_100, 10)))