Given:
The initial mass of an element is 800 grams.
Decay rate = 8.2% per day
Number of days = 15
To find:
The remaining element after 15 days.
Solution:
The exponential decay model is
Where, a is the initial value r is the rate of interest and t is time period.
Putting 
in the above formula, we get
Therefore, the mass of the remaining element is 221.7 grams.
Answer:
Step-by-step explanation:
Given the equation 
Step 1;
Expand the bracket at the right hand side of the equation to have:
Taking the reciprocal of both sides:
Answer:
Exact answer = 10.41666666666666666666666666666pi
Estimated answer = 32.70938
Step-by-step explanation:
Semi circle formula: 1/2 * 4/3 * pi * r^3
r = 2.5
1/2 * 4/3 * pi * 2.5^3
2/3 * pi * 2.5^3
2/3 * pi * 15.625
10.416..... * pi
Exact answer = 10.417pi
We can estimate pi as 3.14
So, 10.417 * 3.14 = 32.70938
Exact answer = 10.41666666666666666666666666666pi
Estimated answer = 32.70938
It’s -9 because when multiplied it’s about -9
