please write only c code as fast as possible

2. InternetLite Corporation is an Internet service provider that charges customers a flat rate of Tk. 30.00 for up to 10 hours of connection time. Additional hours are charged Tk4.00 each. Data file: usage.txt has only the information concerning the number of hour different customers have used the service. For instance, customer has used the service for 10hrs, customer 2 for 20hrs, and customer 3 for Ohrs. So usage.txt has the following info: 10 20 9 Read this information from the file and calculate the total charge in each case, then write the result in a new file bill.txt