Answer:
10.96 hours will take for 85% of the lead to decay.
Step-by-step explanation:
Suppose A represents the amount of Pb-209 at time t,
According to the question,







Let
be the initial amount,


Since, the half-life of 3.3 hours.


Here, 

By substituting the values,



Answer:
m=9
Step-by-step explanation:
Answer: A). V = 1/3(3)(3)(5)
Step-by-step explanation:
• Use the volume of a pyramid formula: V = 1/3Bh, where h is height, V is volume, and B is the base area.
• The base area is length (l) • width (w), so use that to substitute B.
• Substitute the values to get the answer: A). V = 1/3(3)(3)(5)
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Answer:
21
Step-by-step explanation:
21×6students=126
21×5students=105
126-105=21