The purchasing power P (in dollars) of an annual amount ofA dollars after t years of 5% inflation decays according to the following formula.'r P = AeO.05t (a) How long will it be before a pension of $90,000 per year has a purchasing power of $40,000? (Round your answer to two decimal places.) t = yr (b) How much pension A would be needed so that the purchasing power P is $60,000 after 15 years? (Round your answer to the nearest dollar.) $