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# Help!

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Every June 1, an ecologist takes a census of the number of wrens in a state park. She noticed that the number is decreasing by 40% each year. If this trend continues, in what year will the census show that the number of wrens is less than 10% of what it was on June 1, 2004?

I thought the answer was 2008 but it is wrong. Can someone help me please?

Feb 9, 2021

#1
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10 = 100 (1-.4)n     where n is the number of years after 2004 to reach 10%

10/100 = (1-.4)n

.1 = .6n

log .1 = n log .6

n = 4.51    years to reach 10%

this will be in VERY late  2008      but I bet they say it is 2009   because it askes what year the census will show <10%......there will be no new census until 2009 .......   kinda tricky, huh?

Feb 9, 2021

#1
+1

10 = 100 (1-.4)n     where n is the number of years after 2004 to reach 10%

10/100 = (1-.4)n

.1 = .6n

log .1 = n log .6

n = 4.51    years to reach 10%

this will be in VERY late  2008      but I bet they say it is 2009   because it askes what year the census will show <10%......there will be no new census until 2009 .......   kinda tricky, huh?

Guest Feb 9, 2021