An element with mass 590 grams decays by 19.5% per minute. How much of the element is remaining after 15 minutes, to the nearest 10th of a gram
If it decays 19.5% per minute, that means that 100%-19.5%= 80.5% of the element remains after each minute. If it decays for 15 minutes, that means the mass would be calculated by 590*80.5^15= 22.8 grams to the nearest 10th.
Hope it helps!
Neither of those explanations are correct...
The first one states that you multiply 19.5% by 15 to find the total amount of decay. But in the problem you need to raise 19.5% to the 15th power instead of multiply it by 15...
For the second one, decay doesn't work at a common rate...decay is taking off a chunk of the remainder of what's left not of the original total.
Hope this helps!