Answer:
The mass of the radioactive sample after 40 minutes is 12.8 g.
Step-by-step explanation:
The mass of the sample can be found by using the exponential decay equation:

Where:
N(t): is the amount of the sample at time t =?
N₀: is the initial quantity of the sample = 120 g
t = 40 min
λ: is the decay constant = 0.056 min⁻¹
Hence, the mass of the sample after 40 min is:

Therefore, the mass of the radioactive sample after 40 minutes is 12.8 g.
I hope it helps you!
Answer: 67
Step-by-step explanation:
3x^2 + 5x + 25
x = 3
3(3)^2 + 5(3) + 25
3^2 = 9
3(9) + 5(3) + 25
3 * 9 = 27
27 + 5(3) + 25
5 * 3 = 15
27 + 15 + 25
27 + 15 = 42
42 + 25 = 67
Answer:
(- 2, 3 )
Step-by-step explanation:
Given the 2 equations
x + y = 1 → (1)
2y - x = 8 → (2)
Adding the 2 equations term by term will eliminate the x- term
(x - x) + (y + 2y) = (1 + 8), that is
3y = 9 ( divide both sides by 3 )
y = 3
Substitute y = 3 into either of the 2 equations and solve for y
Substituting y = 3 in (1)
x + 3 = 1 ( subtract 3 from both sides )
x = - 2
Solution is (- 2, 3 )
C) 3 ounces
4 × 5 3/4 = 23
the total weight of the snack mix before the cheese puffs were added was 20 ounces. so 23 - 20 = 3 ounces.
An example would be:
Standard:12345678
Expanded: 10000000+2000000+300000+40000+5000+600+70+8
Word: twelve million three hundred forty-five thousand six hundred seventy-eight