I am trying to complete the following question: By pumping the air pressure in a tank is reduced by 15%/second. The percentage of air pressure remaining is fiven by the formula. p=100(0.85)^t Plot p against t for 0 < t < 30s. Deternine the rate of change at 5s & 10s. I have plotted the graph. Verify you anser via calculus. Can anyone please advise which formula is applicable to this?