need help creating a spreadsheet

Suppose that Able Communications is predicting 25% annual growth, on a current base of 90,000 customers. If the growth pattern holds, how many customers will Able have in three years? If it takes about 12 minutes to enter a new customer into the system, how many additional data entry operators will be needed to handle the growth next year? Assume that an operator works about 2,000 hours per year. Also assume a 30% annual attrition rate for existing customers. Show your work in a spreadsheet or chart.

Thank you.