Problem 3-3: A post office sells only 29-cent and 15-cent stamps. Find the number of stamps a customer needs to buy to put $2.70 postage on a package. Find all possible solutions. [Hint: use Diophantine equations). Problem 3-4 Find all solutions to each of the following linear equations: (a). 3x -4 (mod 5); (b). 4x 4 (mod 6). Problem 3-5 Find all solutions tb the following sets of linear equations 7x+3y 3 (mod 7): 4x+2y 5 (mod 7)