EXAMPLE 4 The decay of radioactive elements can sometimes be used to date events from the Earth's past. In a living organism, the ratio of radioactive carbon, carbon-14, to ordinary carbon stays fairly constant during the lifetime of the organism, being approxi- mately equal to the ratio in the organism's atmosphere at the time. After the organism's death, however, no new carbon is ingested, and the proportion of carbon-14 in the organ- ism's remains decreases as the carbon-14 decays. Scientists who do carbon-14 dating use a figure of 5700 years for its half-life. Find the age of a sample in which 10% of the radioactive nuclei originally present have decayed. Activate Windows of Brian wants to buy a house that cost $15000 the bank agreed to give him 80% of cost at 0.09 annual interest on a 30-year loan, what is his monthly payment? is them