1. This graph shows the results of a class survey
2 answers:
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Answer:
D. a is equal to
Step-by-step explanation:
Let us assume that segment PQ is 8 units, so that its midpoint M is at 4 units to both P and Q.
Given that X is the midpoint of PM, this implies that X is at 2 units to both P and M.
Then;
PX = aPQ
⇒ = a x 8
= 8a
Therefore, a must be equal to , so that;
PX = 8a
= 8 x
= 2 units
Thus, a is equal to is the correct option.
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