A salesman is appointed on the basic salary of Rs. 1200 per month and the condition that for every sales of Rs. 10,000 and above Rs. 10,000, he will get 50% of basic salary and 10% of the sales as a reward. This incentive scheme does not operate for the first Rs. 10000 of sales. What should be the value of sales if he wants to earn Rs. 7600 in a particular month?