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The bacteria in a culture grow by 5% in the first hour, get destroyed by 5% in the second hour and again grow b 5% in the third hour. If the count of the bacteria at the end of the third hour is 8.379 * 108 , find the original count of bacteria in the sample.

A.	8*106	B.	8*104
C.	8*107	D.	8*108

Answer and Explanation

Answer:8*108

Explanation:
Let the original count be x. After the 1st hour , the count is x(1+5/100) = 1.05x. After the 2nd hour , the count is 1.05x(1 â€“ 5/100) = 1.05(0.95)x. After the 3rd hour, the count is [1.05(0.95)x]( 1 + 5/100) = (1.05)(0.95) (1.05)x. Therefore, x= 8*108

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