Problem: by selling 22 pens for a rupee a woman loses 10 % . how many for a rupee should he sell in order to gain 50 % ?
Rationale: "d 90 % - - - 22 150 % - - - ? 90 / 150 * 22 = 13"
annotated_formula: inverse(add(divide(divide(const_100, subtract(const_100, 10)), 22), divide(multiply(divide(divide(const_100, subtract(const_100, 10)), 22), 50), const_100)))