Doubling Time. Each exercise gives a doubling time for an exponentially growing quantity. Answer the question (s) about the growth of each quantity.

The doubling time of a population of fruit flies 12 hours. By what factor does the population increase in 36 hours in 1 week?

The answer for this is 8; 16,384

29.The initial population of a town is 15,000, and it grows with a doubling time of 10 years. What will with the population be in 24 years?

The answer for this is 34,461 people; about 79,170 people.

World Population. In 2017, estimated world population was 7.5 billion. Use the given doubling time to predict the world population in 2027, 2067, and 2117.

8.9 billion; 17.8 billion; 42.4 billion

37-40: Approximately Doubling Time Formula. Use the approximately doubling time rule(rule of 70). Discuss whether the formula is valid for the rate described.

37.The Consumer Price Index is increasing at a rate of 3.2% per year. What is its doubling time? By what factor will prices increase in 3 years?

The answer to this is 21.9 years; 1.10.

41-48: Half-Life. Each exercise gives a half-life for an exponentially decaying quantity. Answer the questions about the quantity's decay.

41.The half-life of a radioactive substance is 40 years. If you start with some amount of this substance, what fraction of that amount will remain in 80 years? In 120 years?

The answer to this is 1/4; 1/8.

43.The current population of a threatened animal species is the 1 million, but it is declining with a half-life of the 24 years. How many animals will be left in 30 years? In 70 years?

The answer to this is 0.75; 0.044.

47.Cobalt-56 has a half-life of 77 days. If you start with 1 kilogram of cobalt-56, how much will remain after 100 days? After 200 days?

The answer to this 0.41 kg; 0.17 kg.

49-52: Approximate Half-Life Formula. Use the approximate half-life formula. Discuss whether the formula is valid for the case described.

Urban encroachment is causing the area of a forest to decline at a rate of 6% per year. What is the approximately life-half of the forest? Based on this approximate half-life, about what fraction of the forest will remain in the 50 years?

The answer to this is 11.7 years; 0.05.

This for Math 140. Statistics and Probability. Sacramento City College. I have provided the answers. Please use short answers. PLEASE WATCH GRAMMAR, PUNCTUATION, etc. Use clean writing so it is understandable to read. Thank you.