Radioactive isotopes, and solar cells, are utilized to supply power to space vehicles. Isotope cells regularly lose power due to radioactive decay. On space probe 201, power output of P watts after t days of use is provided by
P(t) = 75e^-0.0025t. Probe will shut down when wattage goes below 35 watts. Correct to nearest whole day, how many days after launch will probe shut down?