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!
Just divide 428.00 by 100 you will get $4.28 each t shirt
Answer:
Math is confusing
Step-by-step explanation:
LOL
<h3>Angles sum up to:</h3><h3>( n - 2 ) × 180 = ( 5 - 2 ) × 180 = 3 × 180 = 540</h3>




Answer:
∠ ABC ≈ 137.9°
Step-by-step explanation:
Using the Cosine rule in Δ ABC
cos B = 
with a = 89, b = 144, c = 65
cos B =
=
=
, thus
B =
( -
) ≈ 137.9° ( to the nearest tenth )