Item are based on the information below :

A cable network provider in a small town has 500 subscribers and he used to collect Rs. 300 per month from each subscriber. He proposes to increase the monthly charges and it is believed from the past experience that for every increase of Rs. 1, one subscriber will discontinue the service. Based on the above in formation, answer the following question :

If Rs x is the monthly increase in subscription amount, then the number of subscribers are

x