3. The number, B, of bacteria in a culture 1 after t hours is given by B(t) = 1000( 23 a) How many bacteria were there initially? b) What is the doubling period, in hours? c) How many bacteria are present after S , 24 h? d) When will there be 128 000 bacteria? 1D A pump reduces the air pressure in a tank by 17% each second. Thus, the percent air pressure, p, is given by p = 100(0.83) where t is the time, in seconds. a) Determine the percent air pressure in the tank after 5 s. b) When will the air pressure be 50% of the starting pressure