Since I'm guessing you're interested in the answers to these questions because you're a poker player, and not because you're interested in the mathematics, you should check out PokerStove: Poker Software and Analysis or StoxEV. The answers to a lot of the more complicated Poker questions are really cumbersome matters from an analytic mathematics standpoint, and you're better off using software.

I just glanced over some of the questions, but assuming in part (c) that you did everything right, calling would be (i) maybe okay in a cash game or in a tournament where you are far off from the final table, but I tend to pass in break even situations against inferiors, and (ii) a HUGE blunder in a sit-and-go or near the end of a tournament.