BTGmoderatorLU wrote:Source: Manhattan Prep

If a certain culture of bacteria increases by a constant factor of x every y minutes, how long will it take for the culture to increase to ten-thousand times its original size?

1) x = 10^y
2) In two minutes, the culture will increase to one hundred times its original size.

The OA is D.

Let's take each statement one by one.

1) x = 10^y

=> 10,000 = 10^y => y = 4 minutes. Sufficient.

2) In two minutes, the culture will increase to one hundred times its original size.

=> Rate = 100^(1/2) = 10 times per minute

Thus, for the culture to increase 10,000 times (= 10^4), it will take 4 minutes. Sufficient.

The correct answer: D

Hope this helps!

-Jay
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