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1. Suppose that the amount of algae in a pond triples every 2 hours. If the pond initially contains 80 pounds of algae, how much algae will be in the pond after 8 hours? (1 point)

a) 720
b) 1,280
c) 6,480
d) 320

User Fiktik
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2 Answers

2 votes
Initially = 80 pounds

It triples every 2 hours

2 hours later = 3(80)
4 hours later = 3(3(80)))
6 hours later = 3(3(3(80)))
8 hours later = 3(3(3(3(3(80)))))
8 hours later =
3^(4) x 80
8 hours later = 6480 (Answer C)

OR

We find the number of 2 hours period in that 8 hours
8 ÷ 2 = 4
It starts at 80 pounds
It tripes every 2 hours
Total algae =
3^(4) x 80 = 6480 (Answer C)


User Guzman Ojero
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8.3k points
3 votes
If it triples every 2 hours, it will triple 4 times. 80x3x3x3x4=6480
User Lini Sax
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