In a certain code language, '-' represents '+', '+' represents 'x', 'x' represents '÷' and '÷' represents '-'. Find out the answer to the following question.
X and Y started a business investing Rs 12000 and Rs 9000 respectively. After 4 months, X left the business and Z joined the business by investing Rs. 18000. At the end of the year, there was a profit of Rs 12500. What is the share (in Rs) of Z in the profit?