please show the each step how you get the answer with the calculater. mention all the key inputs

Three unrelated questions: a) How much does a depositor have to save at the beginning of every 6 months for eleven years to accumulate $17 448.00 if interest is 6.25% compounded semi-annually? b) A contract valued at $81 500.00 requires payment of $3350.00 at the beginning of every six months. If interest is 6.5% compounded semi-annually, what is the term of the contract? c) Geomax pays $8710.00 at the beginning of each year for using a tract of land. What should the company offer the property owner as a purchase price if interest is 10.18% compounded annually