SOLUTION: The population of mosquitos at a local pond triples every hour. If there were 120 mosquitos at the first count predict the number of mosquitos in 12 hours. I think: 120x3=360

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Question 919869: The population of mosquitos at a local pond triples every hour. If there were 120 mosquitos at the first count predict the number of mosquitos in 12 hours.
I think:
120x3=360(1hr)
360x3=1080+360=1440(2hr)
1440x3=4320+1440=5760(3hr)
5760x3=17280+5760=23040(4hr)
23040x3=69120+23040=92160(5hr)
92160x3=276480+92160=368640(6hr)
368640x3=1105920+368640=1474560(7hr)
1474560x3=4423680+1474560=5898240(8hr)
5898240x3=17694720+5898240=23,592,960(9hr)
23592960x3=70778880+23592962=94,371,840(10hr)
94371840x3=(11hr)
(12hr)
am I doing this correctly? please help :)
Found 2 solutions by Alan3354, josgarithmetic:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
The population of mosquitos at a local pond triples every hour. If there were 120 mosquitos at the first count predict the number of mosquitos in 12 hours.
I think:
120x3=360(1hr)
360x3=1080+360=1440(2hr)
1440x3=4320+1440=5760(3hr)
5760x3=17280+5760=23040(4hr)
23040x3=69120+23040=92160(5hr)
92160x3=276480+92160=368640(6hr)
368640x3=1105920+368640=1474560(7hr)
1474560x3=4423680+1474560=5898240(8hr)
5898240x3=17694720+5898240=23,592,960(9hr)
23592960x3=70778880+23592962=94,371,840(10hr)
94371840x3=(11hr)
(12hr)
am I doing this correctly? please help :)
----------------
You got the 1st hour right.
The 2nd hour is 360*3 = 1080.
Don't add 360 to it.
-----
P(t) = 120*3^t
At t = 12 hours:
P(t) = 120^3^12 = 120*531441
P(12) = 63772920

Answer by josgarithmetic(39630) About Me  (Show Source):
You can put this solution on YOUR website!
p, population after time t
t, time passage in hours
120, initial number of mosquitos at t=0

highlight%28p=120%283%29%5Et%29;
Taken using "triple each hour".
t=0, p=120
t=1, p=120*3^1=120*3=360
t=2, p=120*3*3=1080
Read your description carefully: "population of mosquitos triples every hour."

The question is to find p for highlight%28p=120%2A3%5E12%29.
Probably best to either use table of logarithms or scientific calculator.
Do you want to compute highlight_green%283%5E12%29?

p=120%2A531441
p=63772920
highlight%28p=64000000%29, better in keeping with three significant figures.