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.
So; the answer is: A. 5x-2y=1
Answer C. 317.8 would be your answer:) Hope this helps!
Answer:
QR = 65.4 m
Step-by-step explanation:
a. Apply Law of Cosines to find QR:
p² = q² + r² - 2qr × Cos P
p = QR = ?
q = PR = 150 m
r = PQ = 120 m
P = 25°
Plug in the values
p² = 150² + 120² - (2)(150)(120) × Cos(25°)
p² = 22,500 + 14,400 - 36,000 × 0.9063
p² = 36,900 - 32,626.8
p² = 4,273.2
p = √4,273.2
p ≈ 65.4 m (nearest tenth)
QR = 65.4 m
