# math

The number of cases for a disease has reduced by half every 10 years:

1970 - 21,168
1980 - 10,584
1990 - 5,292

Assume N is the number of reported cases t years after 1970. Which is a good model for N(t)?

a) 21,168 (2)^t
b) 21,168 (1/2)^t
c) 21,168 (1/2)^t/10
d) 21,168 (2)^t/10

1. You need t/10, since the number is halved every 10 years.

Since it's halved, that's (1/2)^(t/10)

So, C

posted by Steve

First Name

## Similar Questions

1. ### math

Suppose y , the number of cases of a disease, is reduced by 11% per year. (a) If there are initially 10,000 cases, express y as a function of t , the number of years elapsed. (b) How many cases will there be 6 years from now? (c)
2. ### Math

The table below gives the educational attainment of the U.S. population 25 years and older since 1960. Males- Percentage with 4 years of highschool 1960 39.5% 1970 51.9% 1980 67.3% 1990 77.7% 2000 84.2% 2004 84.8% Percentage with
3. ### calculus

please help me Asap In 1970, the total enrollment in public universities and colleges in a country was 5.1 million students. By 2004, enrollment had risen to 14.3 million students. Assume enrollment can be modeled by exponential
4. ### Intermediate algebra

The number of trout in America, since 1970, is given by the following: y = x2 + 3x + 2 Where x is the number of years and y is the number of trout in the millions. What is the number of trout in the years 1975, 1980, and 1985?
5. ### polynominals

The number of trout in America, since 1970, is given by the following: y = x^2 + 3x + 2, where x is the number of years and y is the number of trout in millions. What is the number of trout in the years 1975, 1980, and 1985?
6. ### Math :)

I need to write a linear function using the following data: Year Life Expectancy In Years 1940 62.5 1950 71.1 1960 73.1 1970 74.7 1980 77.5 1990 78.8 I know the formula is y=mx+b but im not sure how to determine that from what I
7. ### algebra

How do I predict an item's price at a future date (what formula do I use?)? given info. is cost of a Fast food Hamburger \$0.15 in 1960,\$0.30 in 1970, \$0.50 in 1980, \$0.75 in 1990, \$0.89 in 2000. question#1 find average rate of
8. ### Statistics

Episodes of dehydration are common at outdoors music festivals. At a particular large annual event, a first aid team has recorded over the years 85 cases on average per day. In 2018, during a weekend they observe 78, 86, 79, and
9. ### Statistics

Episodes of dehydration are common at outdoors music festivals. At a particular large annual event, a first aid team has recorded over the years 85 cases on average per day. In 2018, during a weekend they observe 78, 86, 79, and