Buffers in Medicine? masteringchemistry?

A) As a technician in a large pharmaceutical research firm, you need to produce 100mL of 1.00 M potium phosphate solution of pH = 7.06. The pKa of H2PO4^- is 7.21. You have 2.0 L of 1.00 M KH2PO4 solution and 1.50 L of 1.00 M K2HPO4 solution, as well as a carboy of pure distilled H2O. How much 1.00 M KH2PO4 will you need to make this solution?