6. a) Determine which amounts of postage can be formed using just 3-cent and 10-cent stamps. b) Prove your answer to (a) using the principle of math- ematical induction. Be sure to state explicitly vour inductive hypothesis in the inductive step c) Prove your answer to (a) using strong induction. Hovw does the inductive hypothesis in this proof differ from that in the inductive hypothesis for a proof using math- ematical induction