Answer:
The probability that 8 mice are required is 0.2428.
Step-by-step explanation:
Given : A scientist inoculates mice, one at a time, with a disease germ until he finds 3 that have contracted the disease. If the probability of contracting the disease is two sevenths.
To find : What is the probability that 8 mice are required? The probability that that 8 mice are required is nothing ?
Solution :
Applying binomial distribution,

Where, p is the probability of success 
q is the probability of failure q=1-p, 
n is total number of trials n=8
r=3
Substitute the values,




Therefore, the probability that 8 mice are required is 0.2428.
A) 8/40 = 1/5
b) 12/40 or 6/20
c) 26/40 or 13/20
Outcomes in a sample space :)
"Interpret the rate of change and the y-intercept.
"
Rate of change is 5. Each ticket costs 5$.
Y-intercept is (0,-17). They spent $17 on supplies before they sold tickets.
(Sorry, you probably already know the answer)