Service tax calculation with example

Dear Sir,

We will provide following service to our clients. then how much service tax need to be deducted .

1. " To provide a list of selected candidate in terms of skills and talent to customer."

2. " To perform hiring services for the company and charge fees for this from the company."

3. "To Charge fees for the website service from the recruiter for using our website."

4. " To Charge fee on providing services for software development".

Please explain with example says invoice of Rs. 250000/- then service tax will be

Thanks in advance