Answer:
a). 8100 bacteria
b). 519 bacteria
c). Infinite
Step-by-step explanation:
Population growth of a bacteria is given by the exponential function,
f(x) = 
Where f(x) = Population after time 't'
= Initial population
r = Growth rate
t = Duration after t hours
If "100 bacteria gets tripled every hour"
300 = 
3 = 1 + 
r = 100×(3 - 1)
r = 200
So the function is, f(x) = 
a). Population after 4 hours,
f(4) = 
= 8100 bacteria
b). Population after 90 minutes Or 1.5 hours
f(1.5) = 
= 519.61
≈ 519 bacteria
c). Population after 72 hours,
f(72) = 
= Infinite
6,395.00 x 2 = 12,790
So $12,790 for the emerald rings.
5,314.00 x 2 = 10,628
So $10,628 for the pearl bracelets.
12,790 + 10,628 = 23,418
So $23,418.00 for all four pieces of jewelry.
Hope it helps!
$.07. You do not write $.7 because that would mean 70 cents and should be written with a 0 at the end anyways. You do not write any dollar amount with a cents sign at the end, because the dollar sign replaces it. You write $.07 because 7 cents means 7/100 (7 one hundredths) so the seven must be written in the hundredths spot. Remember, the hundredth spot is the second number after a decimal.