Consider two local banks. Bank A has $100$ loans$$ outstanding, each for $$$$0\mathrm{.}9$million$,$ that it expects will be repaid today. Each loan has a $7\%$ probability of$$ default, in which case the bank is not repaid anything. The chance of default is independent across all the loans. Bank B has only one loan of $$90$ million$$ outstanding, which it also expects will be repaid today. It also has a $7\%$ probability of not being repaid. Calculate the$$ following:

a$.$ The expected overall payoff of each bank.

b$.$ The standard deviation of the overall payoff of each bank.