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The half-life of a certain element is 5 days. If you started with 948 grams of this element, how much remains after 30 days?

User Itzhaki
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1 Answer

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After 1 half-life, the amount of the element remaining is half of the original amount. After 2 half-lives, the amount remaining is half of the remaining amount after the first half-life. We can continue this pattern until we get to 30 days.

The number of half-lives in 30 days is 30/5 = 6.

So, after 1 half-life, the amount remaining is 948/2 = 474 grams.

After 2 half-lives, the amount remaining is 474/2 = 237 grams.

After 3 half-lives, the amount remaining is 237/2 = 118.5 grams.

After 4 half-lives, the amount remaining is 118.5/2 = 59.25 grams.

After 5 half-lives, the amount remaining is 59.25/2 = 29.625 grams.

After 6 half-lives, the amount remaining is 29.625/2 = 14.8125 grams.

Therefore, after 30 days, 14.8125 grams of the element remains

User Whisperstream
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