Question

Researcher were testing out a new antibiotic on a certain bacteria. They started with 38,000 bacteria. After one treatment with antibiotics, 33,820 were left. After a second treatment, 30,100 bacteria were left. How many bacteria will be left on day 27

Answer 1

1836 bacteria

Explanation:

Now the data is a progression; 38,000, 33,820, 30,100 .........

We can find out what type of progression it is, in this case, we can see that it is a geometric progression because;

r= 33,820/38,000 = 30,100/33,820 = 0.89

So, for a geometric progression;

Un = ar^n-1

Where;

a = 38,000

r = 0.89

n = 27 days

Un = ???

Un = 38,000 * (0.89)^27 - 1

Un = 1836 bacteria