Answer:
a) P(2)=0.270
b) P(X>3)=0.605
c) P=0.410
Step-by-step explanation:
We know that customers arrive at a grocery store at an average of 2.1 per minute. We use the Poisson distribution:

a) In this case: 

Therefore, the probability is P(2)=0.270.
b) In this case: 

Therefore, the probability is P(X>3)=0.605.
c) We know that two customers came in in the first minute. That is why we calculate the probability of at least 5 customers entering the other 2 minutes.
In this case: 

Therefore, the probability is P=0.410.
Answer: $7,500
Step-by-step explanation:
Use the formula: SI = P(1 + rt)
SI = 5000(1 + 0.05[10])
SI = 5000 + 2500
SI = $7,500
After 10 years, your balance should be $7,500
Answer:
Step-by-step explanation:
4(5-2)+(-7)(0.5)
20-8+(-3.5)
12-3.5
8.5
Answer:
We can use the sample about 42 days.
Step-by-step explanation:
Decay Equation:



Integrating both sides


When t=0, N=
= initial amount




.......(1)
.........(2)
Logarithm:
130 days is the half-life of the given radioactive element.
For half life,
,
days.
we plug all values in equation (1)






We need to find the time when the sample remains 80% of its original.







We can use the sample about 42 days.