Answer:
First: 15
Second: 21
Third: 45
Step-by-step explanation:
In order to create the equation we need to represent the evenings with an alebraic term, in thsi case we are going to represent the second evening with an X
Second evening:x
The first night she got 6 fewer calls than the second: Second-6=x-6
The third night she received 3 times the first: 3(first night)=3(x-6)
The equation is First Night plus second night plus third night equals 81.

So the first evening he received 15 calls, the second he received 21 and the third one he received 45.
<span>Formula for exponential decay is:
N = No * e^-kt
N = 1/2(45) = 22.5
No = 45
k = 0.1109
The solution to your problem is as follows:
Let's try to solve the half-life if it is 45 grams, after which, you will now have an idea on how to solve the problem.
22.5 = 45 * e^(-0.1109t)
1/2 = e^(-0.1109t)
ln(1/2) = -0.1109t
t = (ln(1/2))/(-0.1109) = 6.25 days
I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!
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For a square and rectangle it is Area=length*width
A. Is changed or manipulated in the experiment
Correct answer is the 4th choice 16!!!
Hope this helps!!!