Answer:
a) The half life of the substance is 22.76 years.
b) 5.34 years for the sample to decay to 85% of its original amount
Step-by-step explanation:
The amount of the radioactive substance after t years is modeled by the following equation:

In which P(0) is the initial amount and r is the decay rate.
A sample of a radioactive substance decayed to 97% of its original amount after a year.
This means that:

Then



So

(a) What is the half-life of the substance?
This is t for which P(t) = 0.5P(0). So







The half life of the substance is 22.76 years.
(b) How long would it take the sample to decay to 85% of its original amount?
This is t for which P(t) = 0.85P(0). So







5.34 years for the sample to decay to 85% of its original amount
Hi there! Don’t forget your order of operations when doing problems like these. You can remember it by the phrase PEMDAS= parentheses, exponents, multiplication/division, addition/subtraction.
The answer I got was 53/3, or in standard for 3x=53z
Answer:
i think it week 2
Step-by-step explanation:
hope this help
Answer:
72.5 km/h
Step-by-step explanation:
Multiply the km/h by how many hours your going at that speed/total number of hours on trip.
(90x(3.5/8))+(80x(2/8))+(70x(1.5/8))
39.375+20.5+13.125
72.5km/h
Answer:
you should take a picture of the screen bc i cant understand this