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!
Miles per hour = Total miles/ total no of hours
1764 miles divided by 28 hours = 63 mph
Every kilogram is 1,000 grams, but you want 10 kilograms. You can multiply 1,000 10 times (you can also add 1,000 10 times,) giving you the answer > 10,000.
Hope this helped!
Nate
where is the question,it is incomplete. complete the question for your answer.