When we say the rate is Rs. 1000, it means that if you play a 10 second ad once on that radio station in that city, it would cost Rs. 1000. So if you play a 30 second ad once, the cost would be Rs. 1000 X 3 = Rs. 3,000 and if you play that thirty second ad 10 times, it would cost Rs. 3,000 X 10 = Rs. 30,000.