The word problems in this lesson cover the half-life formula and doubling-time formula. An example of a half-life formula word problem is the following: 'The half-life of Carbon-14 is 5730 years. How much of a 100 gram sample will remain after 15,000 years? Round to the hundredth.' An example of a doubling time formula word problem is the following: 'A population of bacteria doubles every 6 hours. By how much will it grow in 3 days?'