Answer:
Let's say that x is sam's age and y is Amy's age
x=y-4
and five years ago:
x-5=(y-5)/2
y-4-5=(y-5)/2
2y-18=y-5
y=13
x=9
then:
sam's age is 9 and Amy's age is 13
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.
Answer:
1 5/6
Step-by-step explanation:
Take how much was added, divide by how much you originally had. 100-80=20. 20/80= 25%
Answer:
F
Step-by-step explanation: