Answer: 
Step-by-step explanation:
We know that the general form of the exponential decay formula is
, where y is final amount remaining after t time, A is the original amount and r is the rate of decay
Now, the ratio of strontium-90 remaining, p , as a function of years, t , since the nuclear accident. 
Hence, the ratio of remaining since the nuclear accident is 
Answer:
3
Step-by-step explanation:
- <em>Each of the seven happy clowns has a red nose.</em>
This means there are (15-7) 8 sad clowns.
- <em>Five of the sad clowns have red noses. </em>
This means out of 8 sad clowns, 5 have red noses. So the clowns that have to act sad and have red noses are (8-5) 3.
Answer:
True
Step-by-step explanation:
Given that:
M = 27, sample of n = 36 scores, µ = 30 and σ = 18.
The z score is used in statistics to determine by how many standard deviations the raw score is above or below the mean. If the z score is positive, the raw score is greater than the mean and if the z score is negative the raw score is less than the mean. The z score is given as:

Given that M = 27, this means that x = 27. Therefore:

This sample mean corresponds to a z-score of z = –1.00.
The answer is -4 + 2 + -0.25 + 0.5.
When you multiply exponents like in the problem, you add them together.
So to find the answer, just subtract the final exponent of 'a' from the original.
6-2=4
The answer should be 4