I'd say the answer would be 8.
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!
It is b Bc if you actually look at the other one it don’t make sense
Answer:
0.2
Step-by-step explanation:
19.62*0.2
Multiply by 0.2
Hope this helps plz hit the crown :D
The answer is A, not sure about the expression though. Sorry