Christopher wants to invest $6200 in a retirement fund that guarantees a return of 9% annually using continuously compounded interest. How much will he have after 20 years? George works at a warehouse installing electronic devices on gas meters. He receives a base pay of $200 and 35 cents for every electronic device installed. Last week, his pay was $437.65. How many electronic devices did he install? Round to the nearest whole number if necessary.