how to do the calculation

Question

i design application using c sharp.
in that i have four column as follows.
Diesel cost, Rental cost ,Diesel service, Service Tax.
Diesel Cost      230291
Rental Cost      231270
Diesel ser         19767
Ser Tax            30124(231270 + 19767 * 12/100).
i am doing service tax calculation at that time service tax is 12 percentage.suppose in next year service tax percentage is 12.36 how to do that calculation.please help me.
Rgds, Narasiman P

Sandeep Singh Shekhawat · Answer

float mDieselCost = 230291;

float mRentalCost = 231270;

float mDieselser = 19767;

float mSerTax = 30124 *(mRentalCost + mDieselser *(float)12.36/100);

Response.Write(mSerTax);