What will the cpm per �g of this DNA be 9.7 days later, expressed in scientific notation?

Radioactive isotopes used in biology undergo exponential radioactive decay over different time-spans for different isotopes. In radioactive decay, the number of neutrons and/or protons of the isotope decrease and the isotope emits "radioactive" energy that can be measured with a Geiger counter, typically as counts per minute (cpm). 32P is a radioactive isotope that has a half-life of 14.3 days (and a decay rate constant, k, of 0.0485), which means that 50% of the original radioactivity of this isotope has been emitted in this 14.3 days. In an experiment with some dividing bacteria in culture, biologists exposed these bacteria to 32P for a half hour, and let's say that the bacteria being used divide every 20 minutes. Thus, lots of bacteria incorporate 32P into their DNA. Immediately after exposure to 32P, they extract the DNA from these bacteria, and measure the radioactivity of 32P in the DNA. They report that it is 1.00 X 108 cpm per �g of DNA. They save this extracted DNA so it can be measured at a later time.