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:
2
Step-by-step explanation:
Since if it's 5 or higher you go up but if it's 4 or lower you stay the same. And since 2.36 doesn't have the .5 it would round to 2
Okay so
#1
4 for 5 would mean each single M&M is 1.25 (5/4)
9 for 25 would mean each single M&M is about 2.78 (25/9)
4 for 5 is the better deal
#2
10 for 35 is 3.50 each (35/10)
12 for 40 is about 3.34 each (40/12)
#3
85 divided by four is 21.25 meaning you'd spend about 22 cents each
the hardware store has a better deal seeing as 19 cents each is cheaper
#4
so 13 divided by 1.4 is about 9.3 so Raisin Bran has less sugar per ounce of cereal