<u>Solution-
</u>
A researcher placed a petri dish with 32,000 bacterial cells. One hour after being placed in the vacuum chamber, the number of cells in the petri dish had halved. Another hour later, the number of cells had again halved.
This can be represented as exponential decreasing function,

Where,
-
a = starting amount = 32000
- r = rate = 50% = 0.5 as the sample becomes halved in each hour
- x = hours
Putting the values,


y-intercept means, where x=0, so

The coordinate of this poin will be (0, 32000)
This means when x=0 or at the starting of the research, the number of bacteria cells was 32000.
After 3 hours, number of bacteria cells will be,



The coordinate of this point will be (3, 4000)
Answer:
29 years
Step-by-step explanation:
The population of the Chinese people is 1.3 bn, and they grow at a rate of 0.49% per year. To get the number of years it requires to reach 1.5 bn, we use this method
after x years, the population will be
1.3 * 1.0049^x
so you just need to solve
1.3 * 1.0049^x = 1.5
1.0049^x = 1.5/1.3
x log 1.0049 = log(1.5/1.3)
x = log(1.5/1.3)/log(1.0049)
x = 0.062 / 0.002122
x = 29.25 years
Therefore, at the rate of 0.49%, the Chinese population of 1.3bn needs 29 years to clock 1.5 bn